JP3954573B2 - Magnetoresistive element, magnetic head, magnetic memory and magnetic recording apparatus using the same - Google Patents

Magnetoresistive element, magnetic head, magnetic memory and magnetic recording apparatus using the same Download PDF

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JP3954573B2
JP3954573B2 JP2003586946A JP2003586946A JP3954573B2 JP 3954573 B2 JP3954573 B2 JP 3954573B2 JP 2003586946 A JP2003586946 A JP 2003586946A JP 2003586946 A JP2003586946 A JP 2003586946A JP 3954573 B2 JP3954573 B2 JP 3954573B2
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康成 杉田
明弘 小田川
望 松川
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    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
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    • G11B5/3906—Details related to the use of magnetic thin film layers or to their effects
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    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
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    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G11B5/3967—Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read
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    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/32—Spin-exchange-coupled multilayers, e.g. nanostructured superlattices
    • H01F10/324—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
    • H01F10/3254—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
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    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
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    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B2005/3996—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices

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Description

本発明は、磁気抵抗効果素子と、これを用いた磁気デバイスである磁気ヘッドおよび磁気メモリならびに磁気記録装置に関する。   The present invention relates to a magnetoresistive effect element, a magnetic head and a magnetic memory, and a magnetic recording apparatus, which are magnetic devices using the magnetoresistive effect element.

近年、磁気抵抗効果（ＭＲ効果）を磁気ヘッドや磁気メモリ（Ｍａｇｎｅｔｉｃ Ｒａｎｄｏｍ Ａｃｃｅｓｓ Ｍｅｍｏｒｙ（ＭＲＡＭ））などに応用するための開発が盛んに行われている。ＭＲ効果は、電子のスピンに依存した伝導現象に基づいており、“磁性層／非磁性層／磁性層”の構造を含む多層膜において、非磁性層を介して隣り合う磁性層同士の磁化方向の相対角度に応じて抵抗値が異なる現象である。一般に、磁化方向が平行の場合に抵抗値が最も小さく、逆に反平行の場合に抵抗値が最も大きくなる。このＭＲ効果を利用した素子を、ＭＲ素子と呼ぶ。ＭＲ素子のうち、非磁性層にＣｕなどの導電性材料を用いた素子をＧＭＲ素子という。また、非磁性層にＡｌ2Ｏ3などの絶縁性材料を用いた素子をＴＭＲ素子という。ＴＭＲ素子では、非磁性層を挟む磁性層のスピン分極率が高いほど大きな磁気抵抗変化率（ＭＲ比）を得ることができる。現在、大きなＭＲ比を発現するＭＲ素子として、このＴＭＲ素子が期待されている。 In recent years, development for applying the magnetoresistive effect (MR effect) to a magnetic head, a magnetic memory (Magnetic Random Access Memory (MRAM)) and the like has been actively performed. The MR effect is based on a conduction phenomenon depending on the spin of electrons, and in a multilayer film including the structure of “magnetic layer / nonmagnetic layer / magnetic layer”, the magnetization directions of adjacent magnetic layers via the nonmagnetic layer This is a phenomenon in which the resistance value varies depending on the relative angle. In general, the resistance value is the smallest when the magnetization directions are parallel, and conversely, the resistance value is the largest when the magnetization directions are antiparallel. An element using this MR effect is called an MR element. Among MR elements, an element using a conductive material such as Cu for the nonmagnetic layer is called a GMR element. An element using an insulating material such as Al 2 O 3 for the nonmagnetic layer is called a TMR element. In the TMR element, a higher magnetoresistance change rate (MR ratio) can be obtained as the spin polarizability of the magnetic layer sandwiching the nonmagnetic layer increases. At present, this TMR element is expected as an MR element that exhibits a large MR ratio.

ＴＭＲ素子を磁気ヘッドやＭＲＡＭなどのデバイスに応用するためには、素子の出力をより向上、安定させる必要がある。また、素子には、デバイスの製造プロセスに耐えることのできる耐熱性が求められている。例えば、磁気ヘッドを製造する工程では、一般に２５０℃〜３００℃程度の熱処理が行われる。ハードディスクドライブ（ＨＤＤ）に搭載される場合には、その動作環境温度（例えば、１５０℃程度）下で長時間安定して動作することが要求される。また、ＭＲ素子をＣＭＯＳ上に作製することによってＭＲＡＭデバイスとして応用する研究が進んでいるが、ＣＭＯＳを製造する工程ではさらに高温の熱処理（例えば、４００℃〜４５０℃）が必要とされる。   In order to apply a TMR element to a device such as a magnetic head or an MRAM, it is necessary to further improve and stabilize the output of the element. Further, the element is required to have heat resistance capable of withstanding the device manufacturing process. For example, in the process of manufacturing a magnetic head, heat treatment is generally performed at about 250 ° C. to 300 ° C. When mounted on a hard disk drive (HDD), it is required to operate stably for a long time under the operating environment temperature (for example, about 150 ° C.). Further, research on application as an MRAM device by fabricating an MR element on a CMOS is advancing, but a higher temperature heat treatment (for example, 400 ° C. to 450 ° C.) is required in the process of manufacturing the CMOS.

しかしながら、従来、トンネル絶縁層と磁性層との間にトンネル接合構造を持つＴＭＲ素子では、３００℃以上の熱処理を行った場合に、磁気抵抗特性（ＭＲ特性）が劣化する、なかでも、素子の出力を示すＭＲ比が低下する傾向がみられる。ＴＭＲ素子を磁気ヘッドやＭＲＡＭなどのデバイスに応用するためには、熱処理などによって素子の温度が上昇した場合にも、よりＭＲ特性が劣化しにくいＴＭＲ素子の開発が重要である。   However, conventionally, in a TMR element having a tunnel junction structure between a tunnel insulating layer and a magnetic layer, magnetoresistance characteristics (MR characteristics) are deteriorated when heat treatment at 300 ° C. or higher is performed. There is a tendency for the MR ratio indicating output to decrease. In order to apply the TMR element to a device such as a magnetic head or an MRAM, it is important to develop a TMR element in which MR characteristics are less likely to deteriorate even when the temperature of the element rises due to heat treatment or the like.

このような状況に鑑み、本発明は、熱処理や素子が動作する際の温度上昇に伴うＭＲ特性の劣化が生じにくい磁気抵抗効果素子、即ち、耐熱性に優れる磁気抵抗効果素子を提供することを目的とする。また、耐熱性に優れる磁気ヘッドおよび磁気メモリ、ならびに磁気記録装置を提供することを目的とする。   In view of such a situation, the present invention provides a magnetoresistive effect element that is unlikely to cause deterioration of MR characteristics due to heat treatment or temperature rise when the element operates, that is, a magnetoresistive effect element having excellent heat resistance. Objective. It is another object of the present invention to provide a magnetic head, a magnetic memory, and a magnetic recording apparatus that are excellent in heat resistance.

上記目的を達成するために、本発明の磁気抵抗効果素子は、トンネル絶縁層と、前記トンネル絶縁層を介して積層された一対の磁性層とを含む多層膜構造を含み、双方の前記磁性層が有する磁化方向の相対角度により抵抗値が異なり、前記磁性層の少なくとも一方が、前記トンネル絶縁層の熱膨張係数に２×１０-6／Ｋを加えた値以下の熱膨張係数を有する磁性膜（以下、低熱膨張磁性膜、ともいう）を含んでいる。なお、本明細書における熱膨張係数とは、常温常圧における線熱膨張係数を意味している。 In order to achieve the above object, a magnetoresistive effect element of the present invention includes a multilayer structure including a tunnel insulating layer and a pair of magnetic layers stacked via the tunnel insulating layer, and both the magnetic layers The magnetic film has a resistance value that differs depending on the relative angle of the magnetization direction of the magnetic layer, and at least one of the magnetic layers has a thermal expansion coefficient equal to or less than a value obtained by adding 2 × 10 −6 / K to the thermal expansion coefficient of the tunnel insulating layer (Hereinafter also referred to as a low thermal expansion magnetic film). In addition, the thermal expansion coefficient in this specification means the linear thermal expansion coefficient in normal temperature normal pressure.

例えば、トンネル絶縁層にＡｌ2Ｏ3、磁性層にＣｏを用いた従来のＭＲ素子では、磁性層の熱膨張係数はトンネル絶縁層の熱膨張係数よりも約５×１０-6／Ｋ大きい。このようなＭＲ素子では、素子の温度が上昇するに伴い、相対的に熱膨張係数が大きい層である磁性層がトンネル絶縁層を圧縮し、トンネル絶縁層に加わる応力負荷が増大すると考えられる。トンネル絶縁層への応力負荷が増大すると、トンネル絶縁層がトンネル特性を維持することが難しくなり、トンネル絶縁層がトンネル特性を失えば、素子のＭＲ特性が劣化することになる。 For example, in a conventional MR element using Al 2 O 3 for the tunnel insulating layer and Co for the magnetic layer, the thermal expansion coefficient of the magnetic layer is about 5 × 10 −6 / K larger than the thermal expansion coefficient of the tunnel insulating layer. In such an MR element, it is considered that as the temperature of the element rises, the magnetic layer, which is a layer having a relatively large thermal expansion coefficient, compresses the tunnel insulating layer, and the stress load applied to the tunnel insulating layer increases. When the stress load on the tunnel insulating layer increases, it becomes difficult for the tunnel insulating layer to maintain the tunnel characteristics, and if the tunnel insulating layer loses the tunnel characteristics, the MR characteristics of the element deteriorate.

これに対して、本発明のＭＲ素子では、トンネル絶縁層の熱膨張係数とほぼ同等もしくはそれ以下の熱膨張係数を有する磁性膜を磁性層が含むことによって、磁性層の熱膨張を原因とするトンネル絶縁層への応力負荷を抑制することができる。このため、高温下においてもトンネル絶縁層がトンネル特性を維持することができ、素子のＭＲ特性の劣化を抑制することができる。なお、低熱膨張磁性膜の熱膨張係数がトンネル絶縁層の熱膨張係数よりも大きい場合であっても、その差が２×１０-6／Ｋ以下であれば、上述の効果を期待できる。 On the other hand, in the MR element of the present invention, the magnetic layer includes a magnetic film having a thermal expansion coefficient substantially equal to or lower than that of the tunnel insulating layer, thereby causing thermal expansion of the magnetic layer. Stress load on the tunnel insulating layer can be suppressed. For this reason, the tunnel insulating layer can maintain the tunnel characteristics even at high temperatures, and the deterioration of the MR characteristics of the element can be suppressed. Even when the thermal expansion coefficient of the low thermal expansion magnetic film is larger than the thermal expansion coefficient of the tunnel insulating layer, the above effect can be expected if the difference is 2 × 10 −6 / K or less.

また、トンネル絶縁層として用いられる絶縁性材料は、一般に圧縮に弱い。一方、磁性層には、展延性に優れた金属材料が主に用いられる。このため、低熱膨張磁性膜の熱膨張係数がトンネル絶縁層の熱膨張係数以下であることが好ましい。この場合、仮に両者の熱膨張係数の差が大きくても、トンネル絶縁層自身の熱膨張によって発生する応力負荷はそれほど大きくならず、素子のＭＲ特性は劣化しにくくなると考えられる。   Insulating materials used as tunnel insulating layers are generally weak against compression. On the other hand, a metal material having excellent spreadability is mainly used for the magnetic layer. For this reason, it is preferable that the thermal expansion coefficient of the low thermal expansion magnetic film is equal to or less than the thermal expansion coefficient of the tunnel insulating layer. In this case, even if the difference in thermal expansion coefficient between the two is large, the stress load generated by the thermal expansion of the tunnel insulating layer itself is not so large, and the MR characteristics of the element are unlikely to deteriorate.

即ち、このようなＭＲ素子とすることによって、耐熱性に優れるＭＲ素子を得ることができる。また、本発明のＭＲ素子では、低熱膨張磁性膜はトンネル絶縁層に接していてもよいし、接していなくてもよい。   That is, by using such an MR element, an MR element having excellent heat resistance can be obtained. In the MR element of the present invention, the low thermal expansion magnetic film may or may not be in contact with the tunnel insulating layer.

次に、本発明の磁気ヘッドは、磁気抵抗効果素子と、前記磁気抵抗効果素子により検知すべき磁界以外の磁界の、前記磁気抵抗効果素子への導入を制限するシールドとを含み、
前記磁気抵抗効果素子は、トンネル絶縁層と、前記トンネル絶縁層を介して積層された一対の磁性層とを含む多層膜構造を含み、双方の前記磁性層が有する磁化方向の相対角度により抵抗値が異なり、前記磁性層の少なくとも一方が、前記トンネル絶縁層の熱膨張係数に２×１０-6／Ｋを加えた値以下の熱膨張係数を有する磁性膜を含んでいる。 Next, the magnetic head of the present invention includes a magnetoresistive effect element and a shield that limits introduction of a magnetic field other than the magnetic field to be detected by the magnetoresistive effect element into the magnetoresistive effect element,
The magnetoresistive effect element includes a multilayer film structure including a tunnel insulating layer and a pair of magnetic layers stacked via the tunnel insulating layer, and has a resistance value depending on a relative angle of a magnetization direction of both the magnetic layers. However, at least one of the magnetic layers includes a magnetic film having a thermal expansion coefficient equal to or less than a value obtained by adding 2 × 10 −6 / K to the thermal expansion coefficient of the tunnel insulating layer.

また、本発明の磁気ヘッドは、磁気抵抗効果素子と、前記磁気抵抗効果素子により検知すべき磁界を前記磁気抵抗効果素子へ導入するヨ−クとを含み、
前記磁気抵抗効果素子は、トンネル絶縁層と、前記トンネル絶縁層を介して積層された一対の磁性層とを含む多層膜構造を含み、双方の前記磁性層が有する磁化方向の相対角度により抵抗値が異なり、前記磁性層の少なくとも一方が、前記トンネル絶縁層の熱膨張係数に２×１０-6／Ｋを加えた値以下の熱膨張係数を有する磁性膜を含んでいてもよい。 The magnetic head of the present invention includes a magnetoresistive effect element and a yoke for introducing a magnetic field to be detected by the magnetoresistive effect element into the magnetoresistive effect element,
The magnetoresistive effect element includes a multilayer film structure including a tunnel insulating layer and a pair of magnetic layers stacked via the tunnel insulating layer, and has a resistance value depending on a relative angle of a magnetization direction of both the magnetic layers. However, at least one of the magnetic layers may include a magnetic film having a thermal expansion coefficient equal to or less than a value obtained by adding 2 × 10 −6 / K to the thermal expansion coefficient of the tunnel insulating layer.

このような磁気ヘッドとすることによって、耐熱性に優れる磁気ヘッドを得ることができる。   By setting it as such a magnetic head, the magnetic head excellent in heat resistance can be obtained.

次に、本発明の磁気メモリは、磁気抵抗効果素子と、前記磁気抵抗効果素子に情報を記録するための情報記録用導体線と、前記情報を読み出すための情報読出用導体線とを含み、
前記磁気抵抗効果素子は、トンネル絶縁層と、前記トンネル絶縁層を介して積層された一対の磁性層とを含む多層膜構造を含み、双方の前記磁性層が有する磁化方向の相対角度により抵抗値が異なり、前記磁性層の少なくとも一方が、前記トンネル絶縁層の熱膨張係数に２×１０-6／Ｋを加えた値以下の熱膨張係数を有する磁性膜を含んでいる。 Next, the magnetic memory of the present invention includes a magnetoresistive effect element, an information recording conductor line for recording information on the magnetoresistive effect element, and an information reading conductor line for reading the information,
The magnetoresistive effect element includes a multilayer film structure including a tunnel insulating layer and a pair of magnetic layers stacked via the tunnel insulating layer, and has a resistance value depending on a relative angle of a magnetization direction of both the magnetic layers. However, at least one of the magnetic layers includes a magnetic film having a thermal expansion coefficient equal to or less than a value obtained by adding 2 × 10 −6 / K to the thermal expansion coefficient of the tunnel insulating layer.

このような磁気メモリとすることによって、耐熱性に優れる磁気メモリを得ることができる。   By using such a magnetic memory, a magnetic memory having excellent heat resistance can be obtained.

次に、本発明の磁気記録装置は、磁気ヘッドと前記磁気ヘッドにより磁気情報を読み出すことができる磁気記録媒体とを含み、
前記磁気ヘッドは、磁気抵抗効果素子と、前記磁気抵抗効果素子により検知すべき磁界以外の磁界の、前記磁気抵抗効果素子への導入を制限するシールドとを含み、
前記磁気抵抗効果素子は、トンネル絶縁層と、前記トンネル絶縁層を介して積層された一対の磁性層とを含む多層膜構造を含み、双方の前記磁性層が有する磁化方向の相対角度により抵抗値が異なり、前記磁性層の少なくとも一方が、前記トンネル絶縁層の熱膨張係数に２×１０-6／Ｋを加えた値以下の熱膨張係数を有する磁性膜を含んでいる。 Next, the magnetic recording apparatus of the present invention includes a magnetic head and a magnetic recording medium from which magnetic information can be read by the magnetic head,
The magnetic head includes a magnetoresistive effect element and a shield that limits introduction of a magnetic field other than the magnetic field to be detected by the magnetoresistive effect element into the magnetoresistive effect element,
The magnetoresistive effect element includes a multilayer film structure including a tunnel insulating layer and a pair of magnetic layers stacked via the tunnel insulating layer, and has a resistance value depending on a relative angle of a magnetization direction of both the magnetic layers. However, at least one of the magnetic layers includes a magnetic film having a thermal expansion coefficient equal to or less than a value obtained by adding 2 × 10 −6 / K to the thermal expansion coefficient of the tunnel insulating layer.

また、本発明の磁気記録装置は、磁気ヘッドと前記磁気ヘッドにより磁気情報を読み出すことができる磁気記録媒体とを含み、
前記磁気ヘッドは、磁気抵抗効果素子と、前記磁気抵抗効果素子により検知すべき磁界を前記磁気抵抗効果素子へ導入するヨ−クとを含み、
前記磁気抵抗効果素子は、トンネル絶縁層と、前記トンネル絶縁層を介して積層された一対の磁性層とを含む多層膜構造を含み、双方の前記磁性層が有する磁化方向の相対角度により抵抗値が異なり、前記磁性層の少なくとも一方が、前記トンネル絶縁層の熱膨張係数に２×１０-6／Ｋを加えた値以下の熱膨張係数を有する磁性膜を含んでいてもよい。 The magnetic recording apparatus of the present invention includes a magnetic head and a magnetic recording medium from which magnetic information can be read by the magnetic head,
The magnetic head includes a magnetoresistive effect element and a yoke for introducing a magnetic field to be detected by the magnetoresistive effect element into the magnetoresistive effect element,
The magnetoresistive effect element includes a multilayer film structure including a tunnel insulating layer and a pair of magnetic layers stacked via the tunnel insulating layer, and has a resistance value depending on a relative angle of a magnetization direction of both the magnetic layers. However, at least one of the magnetic layers may include a magnetic film having a thermal expansion coefficient equal to or less than a value obtained by adding 2 × 10 −6 / K to the thermal expansion coefficient of the tunnel insulating layer.

このような磁気記録装置とすることによって、耐熱性に優れる磁気記録装置を得ることができる。   By using such a magnetic recording apparatus, a magnetic recording apparatus having excellent heat resistance can be obtained.

以下、図面を参照しながら本発明の実施の形態について説明する。なお、以下の実施の形態において、同一の部分には同一の符号を付して重複する説明を省略する場合がある。   Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same parts may be denoted by the same reference numerals and redundant description may be omitted.

最初に、本発明のＭＲ素子について説明する。   First, the MR element of the present invention will be described.

図１は、本発明のＭＲ素子の一例を示す断面図である。図１に示すＭＲ素子は、反強磁性層５、第１磁性層１、トンネル絶縁層３、第２磁性層２が順に積層された多層膜構造を含んでいる。また、第１磁性層１は、磁性膜１１と低熱膨張磁性膜４とを含んでいる。   FIG. 1 is a cross-sectional view showing an example of the MR element of the present invention. The MR element shown in FIG. 1 includes a multilayer structure in which an antiferromagnetic layer 5, a first magnetic layer 1, a tunnel insulating layer 3, and a second magnetic layer 2 are stacked in this order. The first magnetic layer 1 includes a magnetic film 11 and a low thermal expansion magnetic film 4.

図２は、本発明のＭＲ素子の別の一例を示す断面図である。図２に示すＭＲ素子は、反強磁性層５、第１磁性層１、トンネル絶縁層３、第２磁性層２が順に積層された多層膜構造を含んでいる。また、図２に示すＭＲ素子は、第２磁性層２が、磁性膜２１と低熱膨張磁性膜４とを含んでいる。   FIG. 2 is a cross-sectional view showing another example of the MR element of the present invention. The MR element shown in FIG. 2 includes a multilayer structure in which an antiferromagnetic layer 5, a first magnetic layer 1, a tunnel insulating layer 3, and a second magnetic layer 2 are stacked in this order. In the MR element shown in FIG. 2, the second magnetic layer 2 includes a magnetic film 21 and a low thermal expansion magnetic film 4.

図１および図２に示すように、本発明のＭＲ素子は、トンネル絶縁層３を挟む第１磁性層１および第２磁性層２の少なくとも一方が、低熱膨張磁性膜４を含んでいればよい。また、図３に示すように、トンネル絶縁層３を挟む第１磁性層１および第２磁性層２の双方が低熱膨張磁性膜４を含んでいてもよい。図３に示すＭＲ素子では、第１磁性層１は低熱膨張磁性膜４と磁性膜１１とを含み、第２磁性層２は磁性膜２１と低熱膨張磁性膜４とを含んでいる。   As shown in FIGS. 1 and 2, in the MR element of the present invention, it is sufficient that at least one of the first magnetic layer 1 and the second magnetic layer 2 sandwiching the tunnel insulating layer 3 includes a low thermal expansion magnetic film 4. . As shown in FIG. 3, both the first magnetic layer 1 and the second magnetic layer 2 sandwiching the tunnel insulating layer 3 may include a low thermal expansion magnetic film 4. In the MR element shown in FIG. 3, the first magnetic layer 1 includes a low thermal expansion magnetic film 4 and a magnetic film 11, and the second magnetic layer 2 includes a magnetic film 21 and a low thermal expansion magnetic film 4.

このようなＭＲ素子とすることによって、耐熱性に優れるＭＲ素子を得ることができる。   By using such an MR element, an MR element having excellent heat resistance can be obtained.

なお、図１〜図３に示すＭＲ素子では、反強磁性層５が第１磁性層１に接するように配置されており、第１磁性層１を固定磁性層（反強磁性層５によって磁化方向が固定されている磁性層）、第２磁性層２を自由磁性層（第１磁性層に対して相対的に磁化回転が容易である磁性層）とするスピンバルブ型のＭＲ素子となっている。スピンバルブ型のＭＲ素子では、固定磁性層と自由磁性層との間の磁化方向の相対角度をより容易に変化させることができるため、微小な磁界によって動作するデバイスにより適するＭＲ素子とすることができる。また、より小型で大きなＭＲ比を示すＭＲ素子とすることができる。本発明のＭＲ素子は、このようなスピンバルブ型の素子に限定されない。以降に示す例においても同様である。   In the MR element shown in FIGS. 1 to 3, the antiferromagnetic layer 5 is disposed in contact with the first magnetic layer 1, and the first magnetic layer 1 is magnetized by the pinned magnetic layer (antiferromagnetic layer 5). A magnetic layer whose direction is fixed) and a spin valve MR element in which the second magnetic layer 2 is a free magnetic layer (a magnetic layer whose magnetization rotation is relatively easy with respect to the first magnetic layer). Yes. In a spin valve type MR element, the relative angle of the magnetization direction between the pinned magnetic layer and the free magnetic layer can be changed more easily, so that the MR element is more suitable for a device operating with a minute magnetic field. it can. In addition, the MR element can be made smaller and exhibit a large MR ratio. The MR element of the present invention is not limited to such a spin valve type element. The same applies to the examples shown below.

低熱膨張磁性膜は、以下の式（１）の関係を満たす磁性膜であればよい。   The low thermal expansion magnetic film may be a magnetic film satisfying the relationship of the following formula (1).

ｔ1≦ｔ2＋（２×１０-6／Ｋ） （１）
ｔ1：低熱膨張磁性膜の熱膨張係数（１／Ｋ）
ｔ2：トンネル絶縁層の熱膨張係数（１／Ｋ） t 1 ≦ t 2 + (2 × 10 −6 / K) (1)
t 1 : thermal expansion coefficient (1 / K) of low thermal expansion magnetic film
t 2 : thermal expansion coefficient of tunnel insulating layer (1 / K)

なかでも、式ｔ1＝ｔ2の関係を満たす磁性膜（即ち、低熱膨張磁性膜の熱膨張係数とトンネル絶縁層の熱膨張係数とが等しい）であることが好ましい（例えば、実施例に後述するサンプルａ０２、ａ０４など）。また、式ｔ1≦ｔ2−（３×１０-6／Ｋ）の関係を満たす磁性膜であることがより好ましい（例えば、実施例に後述するサンプルａ０３など）。なお、ｔ1の下限値は特に限定されず、例えば、−１×１０-5／Ｋ以上であればよい。 Among them, it is preferable that the magnetic film satisfy the relationship of the expression t 1 = t 2 (that is, the thermal expansion coefficient of the low thermal expansion magnetic film is equal to the thermal expansion coefficient of the tunnel insulating layer) (for example, described later in Examples) Sample a02, a04, etc.). Further, it is more preferable that the magnetic film satisfy the relationship of the formula t 1 ≦ t 2 − (3 × 10 −6 / K) (for example, a sample a03 described later in Examples). In addition, the lower limit value of t 1 is not particularly limited, and may be, for example, −1 × 10 −5 / K or more.

低熱膨張磁性膜の材料は、例えば、インバー合金およびその近傍組成を有する磁性材料を用いればよい。インバー合金は、例えば、Ｆｅ−Ｎｉ、Ｆｅ−Ｐｔ、Ｆｅ−Ｐｄ、Ｆｅ−Ｎｉ−Ｃｏ、Ｆｅ−Ｎｉ−Ｍｎ、Ｆｅ−Ｎｉ−Ｃｒ、Ｆｅ−Ｎｉ−Ｖ、Ｆｅ−Ｎｉ−Ｐｔなどの組成を有する合金を用いればよい。なお、材料の組成を単にＦｅ−Ｎｉのように表記するとき、構成する元素の組成比は特に限定されない。その他の組成についても同様である。   As a material of the low thermal expansion magnetic film, for example, an invar alloy and a magnetic material having a composition in the vicinity thereof may be used. Invar alloys are composed of, for example, Fe-Ni, Fe-Pt, Fe-Pd, Fe-Ni-Co, Fe-Ni-Mn, Fe-Ni-Cr, Fe-Ni-V, and Fe-Ni-Pt. An alloy having the following may be used. Note that when the composition of the material is simply expressed as Fe—Ni, the composition ratio of the constituent elements is not particularly limited. The same applies to other compositions.

なかでも、式Ｆｅx−Ｎｉy−Ｃｏz（ｘ＋ｙ＋ｚ＝１、０．５≦ｘ≦０．７、０．３≦ｙ≦０．４５、０≦ｚ≦０．２）で示される組成を有する合金や、式Ｆｅ1-a−Ｐｔa（０．１５≦ａ≦０．４５）で示される組成を有する合金、式Ｆｅ1-b−Ｐｄb（０．２≦ｂ≦０．４５）で示される組成を有する合金などを用いれば、より耐熱性に優れ、安定したＭＲ特性を有するＭＲ素子を得ることができる。また、低熱膨張磁性膜にインバー合金を用いれば、より大きなＭＲ比を得ることも期待できる。なお、本明細書において組成を示すために用いる数値は、すべて原子組成比に基づく数値とする。 Among them, a composition represented by the formula Fe x -Ni y -Co z (x + y + z = 1,0.5 ≦ x ≦ 0.7,0.3 ≦ y ≦ 0.45,0 ≦ z ≦ 0.2) and an alloy having an alloy having a composition represented by the formula Fe 1-a -Pt a (0.15 ≦ a ≦ 0.45), the formula Fe 1-b -Pd b (0.2 ≦ b ≦ 0.45) If an alloy having a composition represented by the above is used, an MR element having more excellent heat resistance and stable MR characteristics can be obtained. In addition, if an Invar alloy is used for the low thermal expansion magnetic film, it can be expected to obtain a larger MR ratio. In addition, all the numerical values used for showing a composition in this specification shall be a numerical value based on an atomic composition ratio.

また、低熱膨張磁性膜の材料は、例えば、Ｆｅを主成分とするアモルファス磁性材料（Ｆｅ基アモルファス合金）を用いてもよい（ここで主成分とは、原子組成比で０．５以上を示す成分をいう）。なかでも、式Ｆｅ1-c−Ｍc（０．０５≦ｃ≦０．３。また、Ｍは、Ｂ、Ｐ、Ｓｉ、ＺｒおよびＨｆから選ばれる少なくとも一種の元素である）で示される組成を有する磁性材料が好ましい。このような磁性材料は、熱膨張係数が小さく、かつ、アモルファス特性を有している。このため、熱処理によるトンネル絶縁層／磁性層間の界面構造の変化（例えば、界面の凹凸の増大など）や、不純物原子の拡散が抑制され、より耐熱性に優れるＭＲ素子を得ることができる。特に、スピンバルブ型ＭＲ素子では、不純物原子、例えば、反強磁性層に含まれるＭｎ原子などが拡散することによって、磁性層のスピン分極率の低下や、トンネル絶縁層の劣化、破壊などが発生し、ＭＲ特性が劣化する可能性がある。このため、不純物原子の拡散を抑制すれば、より耐熱性に優れるＭＲ素子を得ることができる。 The material of the low thermal expansion magnetic film may be, for example, an amorphous magnetic material (Fe-based amorphous alloy) containing Fe as a main component (here, the main component indicates an atomic composition ratio of 0.5 or more) Refers to ingredients). Among these, a composition represented by the formula Fe 1-c -M c (0.05 ≦ c ≦ 0.3, where M is at least one element selected from B, P, Si, Zr and Hf). A magnetic material having is preferred. Such a magnetic material has a small coefficient of thermal expansion and amorphous characteristics. For this reason, a change in the interface structure between the tunnel insulating layer and the magnetic layer due to heat treatment (for example, an increase in the unevenness of the interface) and the diffusion of impurity atoms are suppressed, and an MR element with better heat resistance can be obtained. In particular, in spin-valve MR elements, impurity atoms, such as Mn atoms contained in the antiferromagnetic layer, diffuse, resulting in a decrease in spin polarizability of the magnetic layer and deterioration or destruction of the tunnel insulating layer. In addition, MR characteristics may be deteriorated. For this reason, if diffusion of impurity atoms is suppressed, an MR element with better heat resistance can be obtained.

なお、低熱膨張磁性膜が、インバー合金およびＦｅ基アモルファス合金の双方を含んでいてもよい。   Note that the low thermal expansion magnetic film may contain both an Invar alloy and an Fe-based amorphous alloy.

低熱膨張磁性膜の膜厚は、例えば、０．３ｎｍ〜５０ｎｍの範囲であればよく、０．５ｎｍ〜１０ｎｍの範囲が好ましい。また、第１磁性層および／または第２磁性層に対して低熱膨張磁性膜が占める割合は、例えば、１０ｖｏｌ％〜１００ｖｏｌ％の範囲であればよい。   The film thickness of the low thermal expansion magnetic film may be, for example, in the range of 0.3 nm to 50 nm, and preferably in the range of 0.5 nm to 10 nm. Further, the ratio of the low thermal expansion magnetic film to the first magnetic layer and / or the second magnetic layer may be, for example, in the range of 10 vol% to 100 vol%.

トンネル絶縁層の材料は、特に限定されず、例えば、Ａｌの酸化物、窒化物および酸窒化物から選ばれる少なくとも１種の化合物を含めばよい。上記化合物は、絶縁特性に優れ、薄膜化が可能であり、ＭＲ特性の再現性にも優れている。Ａｌの酸化物、窒化物は、例えば、Ａｌ2Ｏ3、ＡｌＮなどを用いればよい。なお、Ａｌ2Ｏ3およびＡｌＮの熱膨張係数は、それぞれ、８×１０-6／Ｋ、４×１０-6／Ｋである。 The material of the tunnel insulating layer is not particularly limited, and for example, at least one compound selected from Al oxide, nitride and oxynitride may be included. The above compounds are excellent in insulating properties, can be thinned, and are excellent in reproducibility of MR characteristics. For example, Al 2 O 3 or AlN may be used as the Al oxide or nitride. The thermal expansion coefficients of Al 2 O 3 and AlN are 8 × 10 −6 / K and 4 × 10 −6 / K, respectively.

トンネル絶縁層の膜厚は、有効なトンネル電流を得るために、例えば、０．４ｎｍ〜５ｎｍの範囲であり、３ｎｍ以下の範囲が好ましい。   In order to obtain an effective tunnel current, the film thickness of the tunnel insulating layer is, for example, in the range of 0.4 nm to 5 nm, and preferably in the range of 3 nm or less.

第１磁性層および第２磁性層における低熱膨張磁性膜を除いた部分（図１〜図３に示す磁性膜１１および２１に相当する部分）に用いる磁性材料は、特に限定されない。例えば、Ｃｏ、Ｆｅ、Ｎｉ、Ｃｏ−Ｆｅ、Ｎｉ−Ｆｅ、Ｎｉ−Ｃｏ−Ｆｅなどからなる磁性材料を用いればよい。また、必要に応じて、異なる磁性材料からなる複数の磁性膜を積層してもよい。   The magnetic material used for the part (part corresponding to the magnetic films 11 and 21 shown in FIGS. 1 to 3) excluding the low thermal expansion magnetic film in the first magnetic layer and the second magnetic layer is not particularly limited. For example, a magnetic material made of Co, Fe, Ni, Co—Fe, Ni—Fe, Ni—Co—Fe, or the like may be used. Moreover, you may laminate | stack the several magnetic film which consists of a different magnetic material as needed.

第１磁性層および第２磁性層の膜厚は、低熱膨張磁性膜を含めて、例えば、１ｎｍ〜１０ｎｍの範囲であればよい。   The film thickness of the first magnetic layer and the second magnetic layer may be in the range of, for example, 1 nm to 10 nm including the low thermal expansion magnetic film.

また、図１〜図３に示す例のようにスピンバルブ型のＭＲ素子とする場合、自由磁性層となる磁性層には、例えば、軟磁気特性に優れる磁性材料を用いればよい。軟磁気特性に優れる磁性材料は、例えば、式Ｎｉp−Ｃｏq−Ｆｅrで示される組成を有する金属Ｇを用いればよい。金属Ｇが３成分系である場合（ｐ≠０、ｑ≠０、ｒ≠０）、０．６≦ｐ≦０．９、０＜ｑ≦０．４および０＜ｒ≦０．３で示される範囲、または、０＜ｐ≦０．４、０．２≦ｑ≦０．９５および０＜ｒ≦０．５で示される範囲が好ましい。金属ＧがＮｉとＦｅの２成分系である場合（ｐ≠０、ｑ＝０、ｒ≠０）、０．６≦ｐ＜１および０＜ｒ≦０．４で示される範囲が好ましい。また、金属ＧがＣｏとＦｅの２成分系である場合（ｐ＝０、ｑ≠０、ｒ≠０）、０．７≦ｑ≦０．９５および０．０５≦ｒ≦０．３で示される範囲が好ましい。なお、上記いずれの場合も、ｐ＋ｑ＋ｒ＝１である。 In the case of a spin-valve MR element as in the examples shown in FIGS. 1 to 3, for example, a magnetic material having excellent soft magnetic characteristics may be used for the magnetic layer serving as the free magnetic layer. Magnetic material having excellent soft magnetic characteristics, for example, may be used metal G having a composition represented by the formula Ni p -Co q -Fe r. When the metal G is a ternary system (p ≠ 0, q ≠ 0, r ≠ 0), 0.6 ≦ p ≦ 0.9, 0 <q ≦ 0.4 and 0 <r ≦ 0.3 Or ranges represented by 0 <p ≦ 0.4, 0.2 ≦ q ≦ 0.95 and 0 <r ≦ 0.5. When the metal G is a binary system of Ni and Fe (p ≠ 0, q = 0, r ≠ 0), the ranges represented by 0.6 ≦ p <1 and 0 <r ≦ 0.4 are preferable. Further, when the metal G is a binary system of Co and Fe (p = 0, q ≠ 0, r ≠ 0), it is expressed by 0.7 ≦ q ≦ 0.95 and 0.05 ≦ r ≦ 0.3 The range is preferred. In any of the above cases, p + q + r = 1.

あるいは、Ｃｏ−Ｆｅ−Ｂ、Ｃｏ−Ｍｎ−Ｂ、Ｆｅ−Ｃｏ−Ｓｉなどの３ｄ遷移金属を主体とするアモルファス磁性材料を自由磁性層となる磁性層に用いてもよい。これらの磁性材料も軟磁気特性に優れている。また、必要に応じて、異なる磁性材料からなる複数の磁性膜を積層することによって自由磁性層としてもよい。   Alternatively, an amorphous magnetic material mainly composed of a 3d transition metal such as Co—Fe—B, Co—Mn—B, or Fe—Co—Si may be used for the magnetic layer serving as the free magnetic layer. These magnetic materials are also excellent in soft magnetic properties. Moreover, it is good also as a free magnetic layer by laminating | stacking the some magnetic film which consists of a different magnetic material as needed.

固定磁性層となる磁性層は、例えば、磁気異方性の大きい磁性材料を含む磁性膜、または、それら磁性膜の積層膜を含めばよい。磁気異方性の大きい磁性材料は、例えば、Ｃｏ、Ｃｏ−Ｆｅ合金などを用いればよい。あるいは、Ｃｏ−Ｐｔ合金、Ｆｅ−Ｐｔ合金に代表される、式Ａ−Ｄで示される組成を有する高保磁力磁性材料（Ａは、Ｆｅ、ＣｏおよびＮｉから選ばれる少なくとも１種の元素であり、Ｄは、Ｐｔ、Ｒｈ、Ｐｄ、Ｒｕ、Ｃｒ、Ｒｅ、ＩｒおよびＴａから選ばれる少なくとも１種の元素である）を用いてもよい。その他、Ｃｏ−Ｓｍ合金に代表される磁性元素と希土類元素とからなる合金を用いてもよい。また、スピンバルブ型ＭＲ素子では、反強磁性層によって固定磁性層の磁化方向を固定することができるため、上述した軟磁気特性に優れる磁性材料を固定磁性層となる磁性層に用いてもよい。   The magnetic layer serving as the pinned magnetic layer may include, for example, a magnetic film containing a magnetic material having a large magnetic anisotropy, or a laminated film of these magnetic films. As the magnetic material having a large magnetic anisotropy, for example, Co, a Co—Fe alloy, or the like may be used. Alternatively, a high coercive force magnetic material having a composition represented by Formula AD, represented by a Co—Pt alloy and an Fe—Pt alloy (A is at least one element selected from Fe, Co, and Ni; D may be at least one element selected from Pt, Rh, Pd, Ru, Cr, Re, Ir, and Ta). In addition, an alloy composed of a magnetic element typified by a Co—Sm alloy and a rare earth element may be used. In the spin-valve MR element, the magnetization direction of the pinned magnetic layer can be pinned by the antiferromagnetic layer. Therefore, the above-described magnetic material having excellent soft magnetic characteristics may be used for the magnetic layer serving as the pinned magnetic layer. .

反強磁性層の材料は、特に限定されず、例えば、Ｍｎを含む反強磁性合金（Ｍｎ系反強磁性合金）を用いればよい。Ｍｎ系反強磁性合金は、例えば、式Ｚ−Ｍｎ（Ｚは、Ｐｔ、Ｎｉ、Ｐｄ、Ｃｒ、Ｒｈ、Ｒｅ、Ｉｒ、ＲｕおよびＦｅから選ばれる少なくとも１種の元素）で示される組成を有する合金を用いればよい。なかでも、Ｐｔ−Ｍｎ、Ｐｄ−Ｍｎ、Ｐｄ−Ｐｔ−Ｍｎ、Ｎｉ−Ｍｎ、Ｉｒ−Ｍｎ、Ｃｒ−Ｐｔ−Ｍｎ、Ｒｕ−Ｒｈ−Ｍｎ、Ｆｅ−Ｍｎなどの組成を有する合金が好ましい。これらＭｎ系反強磁性合金と磁性層との間に働く交換結合エネルギーは、他の反強磁性体（例えば、ＮｉＯ、ＣｒＡｌ、α−Ｆｅ2Ｏ3など）を用いた場合よりも大きい。このため、Ｍｎ系反強磁性合金を反強磁性層に用いた場合、外部磁場による攪乱の影響が小さく、より出力が安定したＭＲ素子を得ることができる。 The material of the antiferromagnetic layer is not particularly limited. For example, an antiferromagnetic alloy containing Mn (Mn antiferromagnetic alloy) may be used. The Mn-based antiferromagnetic alloy has a composition represented by, for example, the formula Z-Mn (Z is at least one element selected from Pt, Ni, Pd, Cr, Rh, Re, Ir, Ru, and Fe). An alloy may be used. Among these, alloys having a composition such as Pt—Mn, Pd—Mn, Pd—Pt—Mn, Ni—Mn, Ir—Mn, Cr—Pt—Mn, Ru—Rh—Mn, and Fe—Mn are preferable. The exchange coupling energy acting between these Mn-based antiferromagnetic alloys and the magnetic layer is larger than when other antiferromagnetic materials (for example, NiO, CrAl, α-Fe 2 O 3, etc.) are used. For this reason, when an Mn-based antiferromagnetic alloy is used for the antiferromagnetic layer, it is possible to obtain an MR element that is less affected by external magnetic fields and has a more stable output.

反強磁性層の膜厚は、例えば、５ｎｍ〜３０ｎｍの範囲であればよい。   The film thickness of the antiferromagnetic layer may be in the range of 5 nm to 30 nm, for example.

なお、反強磁性層の下地層として、Ｔａ、Ｎｂ、Ｚｒ、Ｐｔ、Ｃｒなどからなる膜を積層することもできる。また、下地層には、Ｎｉ−Ｆｅ合金や、式Ｎｉ−Ｆｅ−Ｅで示される組成を有する合金（Ｅは、Ｃｒ、Ｖ、Ｎｂ、Ｐｔ、Ｐｄ、Ｒｈ、Ｒｕ、Ｉｒ、ＣｕおよびＡｕから選ばれる少なくとも１種の元素）などを用いてもよい。この場合、反強磁性層の結晶配向性を制御することができ、より出力が安定し、より大きいＭＲ比を示すＭＲ素子を得ることができる。下地層の膜厚は、例えば、１ｎｍ〜１０ｎｍの範囲であればよい。   Note that a film made of Ta, Nb, Zr, Pt, Cr, or the like can be stacked as an underlayer of the antiferromagnetic layer. The underlayer is made of a Ni—Fe alloy or an alloy having a composition represented by the formula Ni—Fe—E (E is composed of Cr, V, Nb, Pt, Pd, Rh, Ru, Ir, Cu, and Au. You may use the at least 1 sort (s) of selected element. In this case, the crystal orientation of the antiferromagnetic layer can be controlled, and an MR element that has a more stable output and a higher MR ratio can be obtained. The film thickness of the underlayer may be in the range of 1 nm to 10 nm, for example.

また、第１磁性層および第２磁性層から選ばれる少なくとも一方の磁性層とトンネル絶縁層との界面に、スピン分極率の大きい磁性材料を含む高スピン分極率層を挿入してもよい。より大きいＭＲ比を示すＭＲ素子を得ることができる。   Further, a high spin polarizability layer containing a magnetic material having a high spin polarizability may be inserted at the interface between at least one magnetic layer selected from the first magnetic layer and the second magnetic layer and the tunnel insulating layer. An MR element showing a larger MR ratio can be obtained.

スピン分極率の大きい磁性材料は、例えば、Ｆｅ3Ｏ4、ＣｒＯ2、ＬａＳｒＭｎＯ、ＬａＣａＳｒＭｎＯなどに代表されるハ−フメタル材料や、あるいは、ＮｉＭｎＳｂ、ＰｔＭｎＳｂなどのホイスラー合金を用いればよい。 As the magnetic material having a high spin polarizability, for example, a half metal material typified by Fe 3 O 4 , CrO 2 , LaSrMnO, LaCaSrMnO or the like, or a Heusler alloy such as NiMnSb or PtMnSb may be used.

高スピン分極率層の膜厚は、例えば、０．５ｎｍ〜１０ｎｍの範囲であればよく、５ｎｍ以下の範囲が好ましい。また、高スピン分極率層には、スピン分極率の大きい磁性材料の単層膜あるいは積層膜を用いればよい。   The film thickness of the high spin polarizability layer may be in the range of 0.5 nm to 10 nm, for example, and is preferably in the range of 5 nm or less. In addition, a single layer film or a laminated film of a magnetic material having a high spin polarizability may be used for the high spin polarizability layer.

従来、高温での熱処理や多数回の熱サイクルによってＭＲ比などの素子特性の劣化が見られたが、その原因の一つとして、上述したように、トンネル絶縁層に加わる応力負荷の増大が考えられる。トンネル絶縁層に対する応力負荷が増加した場合、素子を構成する各層の界面、特に、トンネル絶縁層とそれに隣接する層との界面が乱れ、凹凸の発生などが起きる可能性がある。   Conventionally, degradation of device characteristics such as MR ratio has been observed due to high-temperature heat treatment and numerous thermal cycles. One of the causes is thought to be an increase in stress load applied to the tunnel insulating layer as described above. It is done. When the stress load on the tunnel insulating layer is increased, there is a possibility that the interface of each layer constituting the element, particularly the interface between the tunnel insulating layer and the adjacent layer, is disturbed to generate irregularities.

また、熱処理などによってＭＲ特性が劣化する別の原因として、トンネル絶縁層の界面近傍へ不純物元素が拡散することによるトンネル絶縁層の損傷や、トンネル絶縁層に隣接する磁性層の磁気特性の劣化などが考えられる。一般に、不純物元素は、素子を構成する各層の結晶粒界を通して拡散する。素子が高温になると、各層の結晶粒界が熱膨張により広がることで不純物元素の拡散速度が大きくなり、ＭＲ特性が劣化しやすくなる可能性がある。特に、Ｐｔ−Ｍｎ、Ｉｒ−ＭｎなどのＭｎ系反強磁性合金からなる反強磁性層を含むスピンバルブ型のＭＲ素子では、熱処理によるＭｎの拡散が、ＭＲ特性が劣化する原因の一つである可能性がある。   Another cause of the deterioration of MR characteristics due to heat treatment or the like is damage of the tunnel insulating layer due to diffusion of impurity elements near the interface of the tunnel insulating layer, deterioration of magnetic characteristics of the magnetic layer adjacent to the tunnel insulating layer, etc. Can be considered. In general, an impurity element diffuses through crystal grain boundaries of each layer constituting the element. When the temperature of the element increases, the crystal grain boundary of each layer expands due to thermal expansion, so that the diffusion rate of the impurity element increases and the MR characteristics are likely to deteriorate. In particular, in a spin-valve MR element including an antiferromagnetic layer made of a Mn-based antiferromagnetic alloy such as Pt—Mn or Ir—Mn, diffusion of Mn by heat treatment is one of the causes of deterioration of MR characteristics. There is a possibility.

これに対して、本発明のＭＲ素子では、トンネル絶縁層に隣接する磁性層が低熱膨張磁性膜を含むことによって、トンネル絶縁層に加わる応力負荷の増大が抑制され、耐熱性に優れるＭＲ素子を得ることができる。また、低熱膨張磁性膜の熱膨張率が小さい、即ち、高温下における低熱膨張磁性膜の結晶粒界の広がりが小さいため、不純物元素のトンネル絶縁層の界面近傍への熱拡散が抑制され、耐熱性に優れるＭＲ素子を得ることができる。   In contrast, in the MR element of the present invention, the magnetic layer adjacent to the tunnel insulating layer includes a low thermal expansion magnetic film, so that an increase in stress load applied to the tunnel insulating layer is suppressed, and an MR element having excellent heat resistance is provided. Obtainable. In addition, since the thermal expansion coefficient of the low thermal expansion magnetic film is small, that is, the crystal grain boundary of the low thermal expansion magnetic film is small at high temperatures, thermal diffusion of impurity elements to the vicinity of the interface of the tunnel insulating layer is suppressed, and heat resistance An MR element having excellent properties can be obtained.

本発明のＭＲ素子の別の一例を図４に示す。図４に示すＭＲ素子は、第１磁性層１が低熱膨張磁性膜４を含んでいる。また、低熱膨張磁性膜４は、トンネル絶縁層３と第１磁性層１との界面から離れて配置されている。このように、低熱膨張磁性膜４とトンネル絶縁層３とが接していない場合においても、耐熱性に優れるＭＲ素子を得ることができる。即ち、本発明は、低熱膨張磁性膜４とトンネル絶縁層３とが接している場合に限定されない。なお、図４に示すＭＲ素子は、図１に示すＭＲ素子の低熱膨張磁性膜４とトンネル絶縁層３との間に、磁性膜１２をさらに配置したＭＲ素子である。   Another example of the MR element of the present invention is shown in FIG. In the MR element shown in FIG. 4, the first magnetic layer 1 includes a low thermal expansion magnetic film 4. The low thermal expansion magnetic film 4 is disposed away from the interface between the tunnel insulating layer 3 and the first magnetic layer 1. Thus, even when the low thermal expansion magnetic film 4 and the tunnel insulating layer 3 are not in contact, an MR element having excellent heat resistance can be obtained. That is, the present invention is not limited to the case where the low thermal expansion magnetic film 4 and the tunnel insulating layer 3 are in contact with each other. The MR element shown in FIG. 4 is an MR element in which a magnetic film 12 is further disposed between the low thermal expansion magnetic film 4 and the tunnel insulating layer 3 of the MR element shown in FIG.

このようなＭＲ素子では、例えば、磁性膜１２が低熱膨張磁性膜４よりもスピン分極率が大きい場合には、低熱膨張磁性膜４とトンネル絶縁層３とが直に接している場合に比べてより大きいＭＲ比を得ることができる。ただし、磁性膜１２の熱膨張係数がトンネル絶縁層３の熱膨張係数よりも大きい場合、耐熱性に優れるＭＲ素子を得るためには、トンネル絶縁層３と低熱膨張磁性膜４との距離は、２ｎｍ以下の範囲が好ましく、１ｎｍ以下の範囲がより好ましい。   In such an MR element, for example, when the magnetic film 12 has a higher spin polarizability than the low thermal expansion magnetic film 4, compared with the case where the low thermal expansion magnetic film 4 and the tunnel insulating layer 3 are in direct contact with each other. A larger MR ratio can be obtained. However, when the thermal expansion coefficient of the magnetic film 12 is larger than the thermal expansion coefficient of the tunnel insulating layer 3, in order to obtain an MR element with excellent heat resistance, the distance between the tunnel insulating layer 3 and the low thermal expansion magnetic film 4 is The range of 2 nm or less is preferable, and the range of 1 nm or less is more preferable.

スピンバルブ型のＭＲ素子とする場合、固定磁性層が積層フェリ構造を含んでいてもよい。このようなＭＲ素子の一例を図５に示す。図５に示すＭＲ素子は、固定磁性層である第１磁性層１が、磁性膜１１１、非磁性膜１１２および磁性膜１１３からなる積層フェリ構造を含んでいる。なお、図５に示すＭＲ素子は、図１に示すＭＲ素子の磁性膜１１を積層フェリ構造としたＭＲ素子である。   In the case of a spin valve MR element, the pinned magnetic layer may include a laminated ferrimagnetic structure. An example of such an MR element is shown in FIG. In the MR element shown in FIG. 5, the first magnetic layer 1 that is a pinned magnetic layer includes a laminated ferrimagnetic structure including a magnetic film 111, a nonmagnetic film 112, and a magnetic film 113. The MR element shown in FIG. 5 is an MR element in which the magnetic film 11 of the MR element shown in FIG. 1 has a laminated ferri structure.

ここで積層フェリ構造について説明する。積層フェリ構造とは、図５に示すように、非磁性膜１１２を介して一対の磁性膜１１１および１１３が積層された構造であり、磁性膜１１１と磁性膜１１３とが反強磁性的な交換結合の状態（互いの磁化方向が反平行の状態）にある構造をいう。積層フェリ構造を含むことによって、第１磁性層１の磁化反転磁界はより大きくなり、第１磁性層１の磁化方向を変化させるためには、より大きな外部磁界が必要となる。このため、第１磁性層１の膜厚をより薄くすることが可能になり、ＭＲ素子の小型化を図ることができる。また、同時に、第１磁性層１からの漏洩磁界を、第１磁性層１が積層フェリ構造を含まない場合よりも小さくすることができる。このため、素子を小型化した場合に問題となる、第１磁性層１から自由磁性層である第２磁性層２への漏洩磁界による素子出力の非対称性を低減することができる。   Here, the laminated ferrimagnetic structure will be described. As shown in FIG. 5, the laminated ferrimagnetic structure is a structure in which a pair of magnetic films 111 and 113 are laminated via a nonmagnetic film 112, and the magnetic film 111 and the magnetic film 113 are exchanged antiferromagnetically. A structure in a coupled state (a state in which the magnetization directions are antiparallel). By including the laminated ferrimagnetic structure, the magnetization reversal field of the first magnetic layer 1 becomes larger, and a larger external magnetic field is required to change the magnetization direction of the first magnetic layer 1. For this reason, the film thickness of the first magnetic layer 1 can be further reduced, and the MR element can be miniaturized. At the same time, the leakage magnetic field from the first magnetic layer 1 can be made smaller than when the first magnetic layer 1 does not include a laminated ferrimagnetic structure. For this reason, it is possible to reduce the asymmetry of the element output due to the leakage magnetic field from the first magnetic layer 1 to the second magnetic layer 2 which is a free magnetic layer, which becomes a problem when the element is downsized.

積層フェリ構造に含まれる非磁性膜は、例えば、Ｒｕ、Ｉｒ、Ｒｈ、ＲｅおよびＣｒから選ばれる少なくとも一種の元素を含む膜であればよい。非磁性膜の膜厚は、例えば、０．４ｎｍ〜１．５ｎｍの範囲であればよい。また、非磁性膜は、その両面に磁性膜が接している限り、複数存在していてもよい。   The nonmagnetic film included in the laminated ferri structure may be a film including at least one element selected from Ru, Ir, Rh, Re, and Cr, for example. The film thickness of the nonmagnetic film may be in the range of 0.4 nm to 1.5 nm, for example. A plurality of nonmagnetic films may exist as long as the magnetic films are in contact with both surfaces.

積層フェリ構造に含まれる磁性膜は、例えば、Ｆｅ、Ｃｏ、Ｎｉを含む膜であればよい。磁性膜の膜厚は、例えば、１ｎｍ〜１０ｎｍの範囲であればよい。   The magnetic film included in the laminated ferrimagnetic structure may be a film including, for example, Fe, Co, and Ni. The film thickness of the magnetic film may be in the range of 1 nm to 10 nm, for example.

本発明のＭＲ素子では、トンネル絶縁層は複数配置されていてもよい。例えば、図６に示すように、図１に示すＭＲ素子の第２磁性層２の上にトンネル絶縁層３ａをさらに積層したＭＲ素子であってもよい。また、図７に示すように、図６に示すＭＲ素子のトンネル絶縁層３ａの上に磁性層６をさらに積層したＭＲ素子であってもよい。また、図８に示すように、図７に示すＭＲ素子の磁性層６の上に、磁性層６と反強磁性層５ａとをさらに積層したＭＲ素子であってもよい。   In the MR element of the present invention, a plurality of tunnel insulating layers may be arranged. For example, as shown in FIG. 6, it may be an MR element in which a tunnel insulating layer 3a is further laminated on the second magnetic layer 2 of the MR element shown in FIG. Further, as shown in FIG. 7, an MR element in which a magnetic layer 6 is further laminated on the tunnel insulating layer 3a of the MR element shown in FIG. 6 may be used. Further, as shown in FIG. 8, an MR element in which a magnetic layer 6 and an antiferromagnetic layer 5a are further laminated on the magnetic layer 6 of the MR element shown in FIG. 7 may be used.

このように、複数のトンネル絶縁層を有するＭＲ素子とすることによって、より大きいＭＲ比を得たり、印加電圧の増大に伴うＭＲ比の減少を抑制したりすることができる。また、複数のトンネル絶縁層のうち少なくとも１層が低熱膨張磁性膜を含む磁性層に隣接することによって、耐熱性に優れ、良好なＭＲ特性を示すＭＲ素子を得ることができる。   Thus, by using the MR element having a plurality of tunnel insulating layers, it is possible to obtain a larger MR ratio or to suppress a decrease in the MR ratio accompanying an increase in applied voltage. In addition, since at least one of the plurality of tunnel insulating layers is adjacent to the magnetic layer including the low thermal expansion magnetic film, an MR element having excellent heat resistance and excellent MR characteristics can be obtained.

次に、本発明のＭＲ素子の製造方法について説明する。   Next, a method for manufacturing the MR element of the present invention will be described.

ＭＲ素子を構成する各薄膜の形成には、例えば、パルスレーザデポジション（ＰＬＤ）、イオンビームデポジション（ＩＢＤ）、クラスターイオンビーム、および、ＲＦ、ＤＣ、電子サイクロトロン共鳴（ＥＣＲ）、ヘリコン、誘導結合プラズマ（ＩＣＰ）、対向ターゲットなどの各種スパッタリング法、分子線エピタキシー法（ＭＢＥ）、イオンプレーティング法などを用いればよい。また、これらＰＶＤ法の他に、ＣＶＤ法、メッキ法あるいはゾルゲル法などを用いてもよい。   For forming each thin film constituting the MR element, for example, pulse laser deposition (PLD), ion beam deposition (IBD), cluster ion beam, RF, DC, electron cyclotron resonance (ECR), helicon, induction Various sputtering methods such as coupled plasma (ICP) and a counter target, a molecular beam epitaxy method (MBE), an ion plating method, and the like may be used. In addition to the PVD method, a CVD method, a plating method, a sol-gel method, or the like may be used.

Ａｌ2Ｏ3、ＡｌＮなどからなるトンネル絶縁層の形成は、例えば、次のように行えばよい。まず、Ａｌの薄膜前駆体を作製する。次に、ＯまたはＮを分子、イオン、プラズマ、ラジカルなどとして含む雰囲気中において、ＯまたはＮと上記薄膜前駆体とを温度および時間を制御しながら反応させる。これにより、薄膜前駆体は、ほぼ完全に酸化または窒化され、トンネル絶縁層を得ることができる。また、薄膜前駆体として、ＯまたはＮを化学量論比以下の割合で含んだ不定比化合物を作製してもよい。 The tunnel insulating layer made of Al 2 O 3 , AlN or the like may be formed as follows, for example. First, an Al thin film precursor is prepared. Next, in an atmosphere containing O or N as molecules, ions, plasma, radicals, etc., O or N is reacted with the thin film precursor while controlling the temperature and time. Thereby, the thin film precursor is almost completely oxidized or nitrided, and a tunnel insulating layer can be obtained. Moreover, you may produce the nonstoichiometric compound which contains O or N in the ratio below the stoichiometric ratio as a thin film precursor.

より具体的な例としては、スパッタリング法によってＡｌ2Ｏ3からなるトンネル絶縁層を作製する場合、ＡｌまたはＡｌＯx（ｘ≦１．５）からなる薄膜前駆体をＡｒまたはＡｒ＋Ｏ2雰囲気中で成膜し、これをＯ2またはＯ2＋不活性ガス中で酸化させることを繰り返せばよい。なお、プラズマやラジカルの発生には、ＥＣＲ放電、グロ−放電、ＲＦ放電、ヘリコン、誘導結合プラズマ（ＩＣＰ）などの一般的な手法を用いればよい。 As a more specific example, when forming a tunnel insulating layer made of Al 2 O 3 by sputtering, a thin film precursor made of Al or AlO x (x ≦ 1.5) is formed in an Ar or Ar + O 2 atmosphere. Filming and oxidizing this in O 2 or O 2 + inert gas may be repeated. For the generation of plasma and radicals, general techniques such as ECR discharge, glow discharge, RF discharge, helicon, and inductively coupled plasma (ICP) may be used.

次に、本発明のＭＲ素子を用いたデバイスについて説明する。   Next, a device using the MR element of the present invention will be described.

ＭＲ素子を含み、素子の膜面に垂直な方向に電流を流す磁気デバイスを作製するためは、半導体プロセスやＧＭＲヘッド作製プロセスなどに一般的に用いられている手法を組み合わせて微細加工すればよい。より具体的には、イオンミリング、反応性イオンエッチング（ＲＩＥ）、ＦＩＢ（Ｆｏｃｕｓｅｄ Ｉｏｎ Ｂｅａｍ）などの物理的または化学的エッチング法、微細パターン形成のためのステッパー、電子ビーム（ＥＢ）法などを用いたフォトリソグラフィー技術などを組み合わせればよい。   In order to fabricate a magnetic device that includes an MR element and allows a current to flow in a direction perpendicular to the film surface of the element, it is only necessary to perform microfabrication by combining techniques commonly used in semiconductor processes and GMR head fabrication processes. . More specifically, a physical or chemical etching method such as ion milling, reactive ion etching (RIE), or FIB (Focused Ion Beam), a stepper for forming a fine pattern, or an electron beam (EB) method is used. What is necessary is just to combine the photolithographic technique etc. which were used.

このような方法によって作製された、電極をさらに備えるＭＲ素子の一例を図９に示す。図９に示すＭＲ素子は、基板５０４上に、下部電極５０３、ＭＲ素子５０５、上部電極５０２が順に積層されている。また、ＭＲ素子５０５の周囲、および、上部電極５０２と下部電極５０３との間には層間絶縁膜５０１が配置されている。層間絶縁膜５０１には、上部電極５０２と下部電極５０３との電気的な短絡を防ぐ働きがある。また、図９に示す素子では、上部電極５０２と下部電極５０３とに挟まれたＭＲ素子５０５に電流を流して電圧を読みとることができる。このため、図９に示すような素子の構成とすることによって、ＭＲ素子５０５の膜面に対して垂直な方向に電流を流して出力を読み出すことができる。なお、電極などの表面を平坦化するためには、ＣＭＰやクラスターイオンビームエッチングなどを用いればよい。   An example of an MR element further provided with an electrode manufactured by such a method is shown in FIG. In the MR element shown in FIG. 9, a lower electrode 503, an MR element 505, and an upper electrode 502 are sequentially stacked on a substrate 504. An interlayer insulating film 501 is disposed around the MR element 505 and between the upper electrode 502 and the lower electrode 503. The interlayer insulating film 501 functions to prevent an electrical short circuit between the upper electrode 502 and the lower electrode 503. In the element shown in FIG. 9, the voltage can be read by passing a current through the MR element 505 sandwiched between the upper electrode 502 and the lower electrode 503. For this reason, with the configuration of the element as shown in FIG. 9, it is possible to read the output by flowing a current in a direction perpendicular to the film surface of the MR element 505. Note that CMP, cluster ion beam etching, or the like may be used to planarize the surface of the electrode or the like.

上部電極５０２および下部電極５０３の材料は、例えば、Ｐｔ、Ａｕ、Ｃｕ、Ｒｕ、Ａｌ、ＴｉＮなどの低抵抗の材料（例えば、線抵抗率が１００μΩｃｍ以下）を用いればよい。層間絶縁膜５０１は、例えば、Ａｌ2Ｏ3、ＳｉＯ2などの絶縁性に優れた材料を用いればよい。 The material of the upper electrode 502 and the lower electrode 503 may be a low resistance material such as Pt, Au, Cu, Ru, Al, TiN (for example, a linear resistivity of 100 μΩcm or less). For the interlayer insulating film 501, for example, a material having excellent insulating properties such as Al 2 O 3 and SiO 2 may be used.

本発明のＭＲ素子を用いた磁気ヘッドの一例を図１０に示す。図１０は、ＭＲ素子により検知すべき磁界以外の磁界をＭＲ素子へ導入することを制限するシールドを備えたシールド型磁気ヘッドと、その記録再生方法を示す模式図である。なお、図１０では、説明をわかりやすくするために、ヘッド部５１１を断面図により示す。   An example of a magnetic head using the MR element of the present invention is shown in FIG. FIG. 10 is a schematic diagram showing a shield type magnetic head having a shield for restricting introduction of a magnetic field other than the magnetic field to be detected by the MR element into the MR element, and a recording / reproducing method thereof. In FIG. 10, the head portion 511 is shown in a cross-sectional view for easy understanding.

図１０に示す磁気ヘッドのヘッド部５１１は、記録用の書き込みヘッド部５１２と再生用の再生ヘッド部５１３とを備えている。情報を記録する際には、記録する情報に対応した電流をコイル５１４に流せばよい。コイル５１４に流した電流により発生した磁束が、上部記録コア５１５と上部シールド５１６との間に設けられた記録ギャップ５１７から漏れることによって、磁気記録媒体５１８に記録が行われる。   A head portion 511 of the magnetic head shown in FIG. 10 includes a recording write head portion 512 and a reproducing head portion 513. When recording information, a current corresponding to the information to be recorded may be supplied to the coil 514. Recording is performed on the magnetic recording medium 518 by the magnetic flux generated by the current flowing through the coil 514 leaking from the recording gap 517 provided between the upper recording core 515 and the upper shield 516.

また、情報の再生は、磁気記録媒体５１８に記録されている情報に対応した磁束５１９が、上部シールド５１６と下部シールド５２２との間に設けられた再生ギャップ５２１を通してＭＲ素子５２０に作用することによって行われる。磁束５１９の作用によってＭＲ素子５２０の抵抗値が変化するため、その変化を検出すればよい。   Information is reproduced by the magnetic flux 519 corresponding to the information recorded on the magnetic recording medium 518 acting on the MR element 520 through the reproduction gap 521 provided between the upper shield 516 and the lower shield 522. Done. Since the resistance value of the MR element 520 changes due to the action of the magnetic flux 519, the change may be detected.

このとき、図１０に示す磁気ヘッドでは、上部シールド５１６および下部シールド５２２により、ＭＲ素子によって検知されるべき磁界（即ち、磁束５１９）以外の磁界が制限されるため、高感度の磁気ヘッドとすることができる。また、ＭＲ素子５２０として上述した本発明のＭＲ素子を備えることによって、耐熱性に優れる磁気ヘッドとすることができる。   At this time, in the magnetic head shown in FIG. 10, the upper shield 516 and the lower shield 522 limit the magnetic field other than the magnetic field (that is, the magnetic flux 519) to be detected by the MR element. be able to. Further, by providing the above-described MR element of the present invention as the MR element 520, a magnetic head having excellent heat resistance can be obtained.

上部シールド５１６および下部シールド５２２の材料は、例えば、Ｎｉ−Ｆｅ、Ｆｅ−Ａｌ−Ｓｉ、Ｃｏ−Ｎｂ−Ｚｒ合金などの軟磁性材料を用いればよい。   The material of the upper shield 516 and the lower shield 522 may be a soft magnetic material such as Ni—Fe, Fe—Al—Si, or Co—Nb—Zr alloy.

本発明のＭＲ素子を用いた磁気ヘッドの別の一例を図１１に示す。図１１に示す磁気ヘッドは、ＭＲ素子により検知すべき磁界をＭＲ素子５３１に導入（ガイド）するためのヨーク（上部ヨーク５３３および下部ヨーク５３４）を備えている。また、上部ヨーク５３３と下部ヨーク５３４との間には、絶縁層部５３２が配置されている。上部ヨーク５３３はギャップ５３５を有しており、記録媒体に記録されている情報に対応する信号磁界は、上部ヨーク５３３によりＭＲ素子５３１に導入される。ＭＲ素子５３１は、上部ヨーク５３３および下部ヨーク５３４とＭＲ素子５３１とが磁気的に接続するように、ギャップ５３５と下部ヨーク５３４との間に配置されている。   Another example of a magnetic head using the MR element of the present invention is shown in FIG. The magnetic head shown in FIG. 11 includes yokes (upper yoke 533 and lower yoke 534) for introducing (guide) a magnetic field to be detected by the MR element into the MR element 531. In addition, an insulating layer portion 532 is disposed between the upper yoke 533 and the lower yoke 534. The upper yoke 533 has a gap 535, and a signal magnetic field corresponding to information recorded on the recording medium is introduced into the MR element 531 by the upper yoke 533. The MR element 531 is disposed between the gap 535 and the lower yoke 534 so that the upper yoke 533 and the lower yoke 534 and the MR element 531 are magnetically connected.

図１１に示す磁気ヘッドでは、上部ヨーク５３３、ＭＲ素子５３１および下部ヨーク５３４によって磁気回路が形成されている。このため、ＭＲ素子５３１によって、再生ギャップ５３６で検出した記録媒体の信号磁界を電気信号として検出することができる。また、ＭＲ素子として、上述した本発明のＭＲ素子を備えることによって、耐熱性に優れる磁気ヘッドとすることができる。なお、再生ギャップ５３６の長さ（再生ギャップ長）は、例えば、０．２μｍ以下の範囲である。   In the magnetic head shown in FIG. 11, a magnetic circuit is formed by the upper yoke 533, the MR element 531, and the lower yoke 534. Therefore, the MR element 531 can detect the signal magnetic field of the recording medium detected by the reproduction gap 536 as an electric signal. Further, by providing the MR element of the present invention described above as the MR element, a magnetic head having excellent heat resistance can be obtained. Note that the length of the reproduction gap 536 (reproduction gap length) is, for example, in a range of 0.2 μm or less.

ここで、図１１に示す磁気ヘッドのＭＲ素子５３１周辺の構造について説明する。図１２は、図１１に示す磁気ヘッドのＭＲ素子５３１を含む部分をI−I’
で切断した断面図である。なお、図１１に示す磁気ヘッドのＭＲ素子５３１周辺の構造が、必ず図１２に示す構造である必要はなく、図１２に示す構造は一例にすぎない。 Here, the structure around the MR element 531 of the magnetic head shown in FIG. 11 will be described. FIG. 12 shows a portion including the MR element 531 of the magnetic head shown in FIG.
It is sectional drawing cut | disconnected by. The structure around the MR element 531 of the magnetic head shown in FIG. 11 is not necessarily the structure shown in FIG. 12, and the structure shown in FIG. 12 is merely an example.

図１２に示すように、ＭＲ素子５３１の周囲には、ＭＲ素子５３１の膜面に垂直な方向に電流を流すためのリード部５３７と、ＭＲ素子５３１の自由磁性層の磁化方向を制御するためのハードバイアス部５３８とが配置されている。図１２に示す例では、リード部５３７とヨークとが絶縁層部５３２によって電気的に絶縁されているが、リード部５３７とヨークとは電気的に接続されていてもよい。この場合、ヨークおよびリード部を兼用にすることができる。また、ＭＲ素子５３１にトンネル電流を安定して流すために、ハードバイアス部５３８とＭＲ素子５３１とが電気的に絶縁されていることが好ましい。   As shown in FIG. 12, a lead portion 537 for flowing a current in a direction perpendicular to the film surface of the MR element 531 around the MR element 531 and a magnetization direction of the free magnetic layer of the MR element 531 are controlled. The hard bias unit 538 is arranged. In the example shown in FIG. 12, the lead portion 537 and the yoke are electrically insulated by the insulating layer portion 532, but the lead portion 537 and the yoke may be electrically connected. In this case, the yoke and the lead portion can be shared. Further, it is preferable that the hard bias portion 538 and the MR element 531 are electrically insulated in order to allow a tunnel current to flow stably through the MR element 531.

絶縁層部５３２の材料は、例えば、Ａｌ2Ｏ3、ＡｌＮ、ＳｉＯ2などを用いればよい。上部ヨーク５３３および下部ヨーク５３４の材料は、一般的な軟磁性材料、例えば、Ｆｅ−Ｓｉ−Ａｌ、Ｎｉ−Ｆｅ、Ｎｉ−Ｆｅ−Ｃｏ、Ｃｏ−Ｎｂ−Ｚｒ、Ｃｏ−Ｔａ−Ｚｒ、Ｆｅ−Ｔａ−Ｎなどを用いればよい。これら軟磁性材料からなる膜と、Ｔａ、Ｒｕ、Ｃｕなどからなる非磁性膜との積層膜を用いてもよい。ハードバイアス部５３８の材料は、例えば、Ｃｏ−Ｐｔ合金などを用いればよい。リード部５３７の材料は、一般的に低い電気抵抗を示す、Ｃｕ、Ａｕ、Ｐｔなどを用いればよい。なお、下部ヨーク５３４には、磁性材料からなる基板（例えば、Ｍｎ−Ｚｎフェライト基板）を用いてもよい。 For example, Al 2 O 3 , AlN, SiO 2 or the like may be used as the material of the insulating layer portion 532. The material of the upper yoke 533 and the lower yoke 534 is a general soft magnetic material such as Fe—Si—Al, Ni—Fe, Ni—Fe—Co, Co—Nb—Zr, Co—Ta—Zr, Fe— Ta-N or the like may be used. A laminated film of a film made of these soft magnetic materials and a nonmagnetic film made of Ta, Ru, Cu or the like may be used. As a material of the hard bias portion 538, for example, a Co—Pt alloy or the like may be used. As a material for the lead portion 537, Cu, Au, Pt, or the like, which generally shows a low electric resistance, may be used. For the lower yoke 534, a substrate made of a magnetic material (for example, a Mn—Zn ferrite substrate) may be used.

なお、図１１に示すようなヨークを備えた磁気ヘッドの場合、ＭＲ素子５３１の自由磁性層は、上部ヨーク５３３側に配置されることが好ましい。   In the case of a magnetic head including a yoke as shown in FIG. 11, the free magnetic layer of the MR element 531 is preferably disposed on the upper yoke 533 side.

一般に、図１１に示すようなヨーク型磁気ヘッドは、図１０に示すようなシールド型磁気ヘッドと比べて、感度では劣るものの、シ−ルドギャップ中にＭＲ素子を配置する必要がないため、狭ギャップ化では有利である。また、ＭＲ素子が記録媒体に対して露出していないため、記録媒体と磁気ヘッドとの接触などによるヘッドの破損や摩耗が少なく、信頼性の面で優れている。このため、ヨーク型磁気ヘッドは、磁気テープを記録媒体とするストリーマーなどに用いる場合に、特に優れているといえる。   In general, the yoke type magnetic head as shown in FIG. 11 is inferior in sensitivity to the shield type magnetic head as shown in FIG. 10, but it is not necessary to arrange an MR element in the shield gap. It is advantageous in forming a gap. Further, since the MR element is not exposed to the recording medium, the head is not damaged or worn due to contact between the recording medium and the magnetic head, and is excellent in terms of reliability. For this reason, it can be said that the yoke type magnetic head is particularly excellent when used for a streamer using a magnetic tape as a recording medium.

上述した本発明の磁気ヘッドを用いて、ＨＤＤなどの磁気記録装置を構成することができる。図１３に、本発明の磁気記録装置の一例を示す。図１３に示す磁気記録装置５４５は、磁気ヘッド５４１、駆動部５４２、情報が記録される磁気記録媒体５４３および信号処理部５４４を備えている。このとき、磁気ヘッド５４１として上述した本発明の磁気ヘッドを用いることによって、耐熱性に優れる磁気記録装置とすることができる。   A magnetic recording apparatus such as an HDD can be configured using the magnetic head of the present invention described above. FIG. 13 shows an example of the magnetic recording apparatus of the present invention. A magnetic recording device 545 shown in FIG. 13 includes a magnetic head 541, a drive unit 542, a magnetic recording medium 543 on which information is recorded, and a signal processing unit 544. At this time, by using the above-described magnetic head of the present invention as the magnetic head 541, a magnetic recording apparatus having excellent heat resistance can be obtained.

次に、本発明のＭＲ素子をメモリ素子として用いた磁気メモリ（ＭＲＡＭ）の一例を図１４に示す。図１４に示すＭＲＡＭでは、ＭＲ素子６０１は、ＣｕやＡｌなどからなるビット（センス）線６０２とワ−ド線６０３との交点にマトリクス状に配置されている。ビット線は情報再生用導体線に、ワード線は情報記録用導体線にそれぞれ相当する。これらの線に信号電流を流した時に発生する合成磁界により、ＭＲ素子６０１に信号が記録される。信号は、「オン」状態となったラインが交差する位置に配置された素子（図１４では、ＭＲ素子６０１ａ）に記録される（２電流一致方式）。   Next, an example of a magnetic memory (MRAM) using the MR element of the present invention as a memory element is shown in FIG. In the MRAM shown in FIG. 14, the MR elements 601 are arranged in a matrix at the intersections of bit (sense) lines 602 and word lines 603 made of Cu, Al, or the like. The bit line corresponds to an information reproducing conductor line, and the word line corresponds to an information recording conductor line. A signal is recorded in the MR element 601 by a combined magnetic field generated when a signal current is passed through these lines. The signal is recorded in the element (MR element 601a in FIG. 14) arranged at the position where the line in the “ON” state intersects (two current matching method).

図１５〜図１７を参照して、ＭＲＡＭの動作についてさらに説明する。図１５Ａ、図１６Ａおよび図１７Ａには、書き込み動作の基本例が示されている。また、図１５Ｂ、図１６Ｂおよび図１７Ｂには、読み込み動作の基本例が示されている。ＭＲ素子７０１は、上述した本発明のＭＲ素子である。   The operation of the MRAM will be further described with reference to FIGS. 15A, 16A and 17A show a basic example of the write operation. 15B, 16B, and 17B show basic examples of the reading operation. The MR element 701 is the MR element of the present invention described above.

図１５Ａおよび図１５Ｂに示すＭＲＡＭでは、ＭＲ素子７０１の磁化状態を個別に読みとるために、素子ごとに、ＦＥＴなどのスイッチ素子７０５が配置されている。このＭＲＡＭは、ＣＭＯＳ基板上への作製に適している。図１６Ａおよび図１６Ｂに示すＭＲＡＭでは、素子ごとに、非線形素子７０６が配置されている。非線形素子７０６は、例えば、バリスタ、トンネル素子、上述の３端子素子などを用いればよい。非線形素子の代わりに整流素子を用いてもよい。このＭＲＡＭは、ダイオ−ドの成膜プロセスを用いれば、安価なガラス基板上にも作製できる。図１７Ａおよび図１７Ｂに示すＭＲＡＭでは、図１５〜図１６に示すようなスイッチ素子や非線形素子を用いることなく、ワ−ド線７０４とビット線７０３との交点に、ＭＲ素子７０１が直接配置されている。このＭＲＡＭでは読み出し時に複数の素子に電流が流れることになるため、読み出し精度の観点から、例えば、素子数を１００００以下に制限することが好ましい。   In the MRAM shown in FIGS. 15A and 15B, in order to individually read the magnetization state of the MR element 701, a switch element 705 such as an FET is arranged for each element. This MRAM is suitable for production on a CMOS substrate. In the MRAM shown in FIGS. 16A and 16B, a non-linear element 706 is arranged for each element. As the nonlinear element 706, for example, a varistor, a tunnel element, the above-described three-terminal element, or the like may be used. A rectifying element may be used instead of the nonlinear element. This MRAM can be manufactured on an inexpensive glass substrate by using a diode film forming process. In the MRAM shown in FIGS. 17A and 17B, the MR element 701 is directly arranged at the intersection of the word line 704 and the bit line 703 without using the switching elements and nonlinear elements as shown in FIGS. ing. In this MRAM, a current flows through a plurality of elements at the time of reading. Therefore, from the viewpoint of reading accuracy, for example, it is preferable to limit the number of elements to 10,000 or less.

また、図１５〜図１７に示すＭＲＡＭでは、ビット線７０３が、素子に電流を流して抵抗変化を読みとるセンス線としても用いられている。しかし、ビット電流による誤動作や素子破壊を防ぐため、センス線とビット線とを別途配置してもよい。この場合、ビット線を、素子と電気的な絶縁を保ちながら、かつ、センス線と平行に配置することが好ましい。なお、書き込み時における消費電力の観点から、ワ−ド線、ビット線とＭＲ素子との間隔は、例えば、５００ｎｍ以下であればよい。   In the MRAM shown in FIGS. 15 to 17, the bit line 703 is also used as a sense line for reading a resistance change by passing a current through the element. However, a sense line and a bit line may be separately arranged in order to prevent malfunctions and element destruction due to a bit current. In this case, it is preferable to arrange the bit line in parallel with the sense line while maintaining electrical insulation from the element. From the viewpoint of power consumption at the time of writing, the distance between the word line, bit line and MR element may be, for example, 500 nm or less.

以下、実施例を用いて本発明をさらに詳細に説明するが、本発明は以下に示す例に限定されない。   EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited to the example shown below.

熱酸化膜付Ｓｉ基板（３インチφ）上に、マグネトロンスパッタリング法を用いて、各実施例に記載する膜構成のＭＲ素子を作製し、そのＭＲ特性を評価した。   An MR element having the film configuration described in each example was fabricated on a Si substrate (3 inches φ) with a thermal oxide film by using a magnetron sputtering method, and its MR characteristics were evaluated.

（実施例１）
熱酸化膜付Ｓｉ基板／Ｔａ（３）／Ｃｕ（５０）／Ｔａ（３）／Ｐｔ−Ｍｎ（３０）／Ｃｏ−Ｆｅ（１）／Ｘ／Ａｌ2Ｏ3（０．６）／Ｎｉ0.8Ｆｅ0.2（５） Example 1
Si substrate with thermal oxide film / Ta (3) / Cu (50) / Ta (3) / Pt—Mn (30) / Co—Fe (1) / X / Al 2 O 3 (0.6) / Ni 0.8 Fe 0.2 (5)

ここで、括弧内の数値は膜厚を示している。単位はｎｍであり、以下、同様にして膜厚を表示する。ただし、Ａｌ2Ｏ3の値は、酸化処理前のＡｌの設計膜厚値（合計値）である（ＡｌＮにおける窒化処理を含め、以下同様である）。Ａｌ2Ｏ3は、Ａｌを０．３〜０．７ｎｍの膜厚で成膜した後、２６．３ｋＰａ（２００Ｔｏｒｒ）の酸素含有雰囲気中において１分間の酸化を繰り返して作製した。 Here, the numerical value in parentheses indicates the film thickness. The unit is nm, and hereinafter, the film thickness is displayed in the same manner. However, the value of Al 2 O 3 is a design film thickness value (total value) of Al before the oxidation treatment (including the nitridation treatment in AlN, and so on). Al 2 O 3 was formed by forming an Al film with a thickness of 0.3 to 0.7 nm and then repeatedly oxidizing for 1 minute in an oxygen-containing atmosphere of 26.3 kPa (200 Torr).

基板上のＴａ（３）／Ｃｕ（５０）は下部電極であり、下部電極とＰｔ−Ｍｎ層との間のＴａ（３）は下地層である。Ｐｔ−Ｍｎ層は反強磁性層であり、本実施例のＭＲ素子は、スピンバルブ型のＭＲ素子である。なお、Ｐｔ−Ｍｎ層およびＣｏ−Ｆｅ層の組成は、それぞれＰｔ0.48Ｍｎ0.52およびＣｏ0.75Ｆｅ0.25であった。 Ta (3) / Cu (50) on the substrate is a lower electrode, and Ta (3) between the lower electrode and the Pt—Mn layer is an underlayer. The Pt—Mn layer is an antiferromagnetic layer, and the MR element of this example is a spin valve MR element. The compositions of the Pt—Mn layer and the Co—Fe layer were Pt 0.48 Mn 0.52 and Co 0.75 Fe 0.25 , respectively.

Ｘは、以下の表１に示す組成を有する磁性材料である。本実施例では、従来例として２種類（サンプルａ０１およびサンプルａ０８）、実施例として６種類（サンプルａ０２〜サンプルａ０７）のサンプルを準備した。   X is a magnetic material having the composition shown in Table 1 below. In this example, two types (sample a01 and sample a08) were prepared as conventional examples, and six types (sample a02 to sample a07) were prepared as examples.

各サンプルの成膜は、圧力が１．３×１０-6Ｐａ（１×１０-8Ｔｏｒｒ）以下になるまで排気した後、Ａｒガスが約０．１Ｐａ（約０．８ｍＴｏｒｒ）の雰囲気になるように調整したチャンバー内で行った。また、成膜の際には、サンプルの膜面に対して平行な方向に磁界（８．０×１０3Ａ／ｍ（１００Ｏｅ））を印加した。その後、各サンプルとも、フォトリソグラフィー法を用いて図９に示すようなメサ型に微細加工し、層間絶縁膜としてＡｌ2Ｏ3を用いて周囲を絶縁した後、上部にスルーホールを開け、この上にＣｕ（５０）／Ｔａ（３）からなる上部電極を形成してＭＲ素子を作製した。素子サイズは全て１μｍ×２μｍとした。作製したＭＲ素子は、２８０℃、４．０×１０5Ａ／ｍ（５ｋＯｅ）の真空磁界中で１時間保持し、Ｐｔ‐Ｍｎ層に磁気異方性を付与した。 In the film formation of each sample, after evacuating until the pressure becomes 1.3 × 10 −6 Pa (1 × 10 −8 Torr) or less, the atmosphere of Ar gas becomes about 0.1 Pa (about 0.8 mTorr). In a chamber adjusted as described above. In film formation, a magnetic field (8.0 × 10 3 A / m (100 Oe)) was applied in a direction parallel to the film surface of the sample. After that, each sample was finely processed into a mesa shape as shown in FIG. 9 using a photolithography method, and the periphery was insulated using Al 2 O 3 as an interlayer insulating film, and then a through hole was opened in the upper portion. An upper electrode made of Cu (50) / Ta (3) was formed thereon to produce an MR element. All element sizes were 1 μm × 2 μm. The produced MR element was held in a vacuum magnetic field of 280 ° C. and 4.0 × 10 5 A / m (5 kOe) for 1 hour to impart magnetic anisotropy to the Pt—Mn layer.

上記のように準備した各サンプルに対して熱処理を実施し、熱処理温度によるＭＲ特性の変化（ＭＲ特性の熱処理温度依存性）を評価した。熱処理の方法およびＭＲ特性の測定方法を以下に示す。   Each sample prepared as described above was subjected to heat treatment, and changes in MR characteristics depending on the heat treatment temperature (dependence of MR characteristics on heat treatment temperature) were evaluated. A heat treatment method and a method for measuring MR characteristics are shown below.

まず、真空無磁界中において、表１に示す各熱処理温度にまでサンプルを加熱し、３０分間保持した。その後、サンプルを室温まで冷却し、熱処理を完了した。熱処理を完了した後、各サンプルのＭＲ特性としてＭＲ比を求めた。ＭＲ比を求めるための磁気抵抗の測定は、固定磁性層の磁化容易軸方向と同方向に最大４．０×１０5Ａ／ｍの外部磁界を印加しながら、直流四端子法を用いて行った。ＭＲ比は、磁気抵抗の測定で得られた最大抵抗値をＲmax、最小抵抗値をＲminとして、次式（２）により算出した。ＭＲ特性の測定方法は、以降の実施例においても同様である。 First, in a vacuum magnetic field, the sample was heated to each heat treatment temperature shown in Table 1 and held for 30 minutes. Thereafter, the sample was cooled to room temperature to complete the heat treatment. After completing the heat treatment, the MR ratio was determined as the MR characteristic of each sample. The measurement of magnetoresistance for obtaining the MR ratio is performed using the DC four-terminal method while applying an external magnetic field of 4.0 × 10 5 A / m at the maximum in the same direction as the easy axis of magnetization of the pinned magnetic layer. It was. The MR ratio was calculated by the following equation (2), where R max was the maximum resistance value obtained by measurement of the magnetic resistance and R min was the minimum resistance value. The method for measuring MR characteristics is the same in the following embodiments.

ＭＲ比＝｛（Ｒmax−Ｒmin）／Ｒmin｝×１００（％） （２） MR ratio = {(R max −R min ) / R min } × 100 (%) (2)

表１に、各サンプルにおけるＸの組成、膜厚および熱膨張係数とともに、熱処理温度依存性の結果を示す。熱膨張係数の単位は（１／Ｋ）である（以降の実施例においても同様である）。なお、サンプルａ０３では、Ｘのうち、Ｆｅ0.7Ｐｔ0.3（２）のみが低熱膨張磁性膜に相当し、Ｃｏ（１．５）は、図４における磁性膜１２に相当している。また、サンプルａ０３における熱膨張係数は、低熱膨張磁性膜であるＦｅ0.7Ｐｔ0.3層のみの値である。 Table 1 shows the results of the heat treatment temperature dependence together with the X composition, film thickness, and thermal expansion coefficient of each sample. The unit of thermal expansion coefficient is (1 / K) (the same applies to the following examples). In sample a03, only Fe 0.7 Pt 0.3 (2) of X corresponds to the low thermal expansion magnetic film, and Co (1.5) corresponds to the magnetic film 12 in FIG. Further, the thermal expansion coefficient in sample a03 is a value of only the Fe 0.7 Pt 0.3 layer which is a low thermal expansion magnetic film.

低熱膨張磁性膜およびトンネル絶縁層の熱膨張係数は、それぞれの熱膨張量を光干渉法により測定し（測定温度範囲０〜４５０℃、昇温レート１℃／分、常圧下）、測定した熱膨張量のグラフの２５℃における接線の傾きより求めた。なお、測定は、各サンプルと同様の低熱膨張磁性膜およびトンネル絶縁層を石英ガラス上に作製して行った。熱膨張係数の測定方法は、以降の実施例においても同様である。   The thermal expansion coefficients of the low thermal expansion magnetic film and the tunnel insulating layer were determined by measuring the respective thermal expansion amounts by optical interference method (measurement temperature range 0 to 450 ° C., temperature increase rate 1 ° C./min, under normal pressure). It calculated | required from the inclination of the tangent in 25 degreeC of the graph of expansion amount. The measurement was performed by producing a low thermal expansion magnetic film and a tunnel insulating layer similar to each sample on quartz glass. The method for measuring the thermal expansion coefficient is the same in the following examples.

なお、トンネル絶縁層であるＡｌ2Ｏ3の熱膨張係数は、８×１０-6／Ｋであった。 In addition, the thermal expansion coefficient of Al 2 O 3 which is a tunnel insulating layer was 8 × 10 −6 / K.

Figure 0003954573
Figure 0003954573

表１に示すように、Ｘとして、熱膨張係数がＡｌ2Ｏ3の熱膨張係数よりも５×１０-6／Ｋ大きい軟磁性材料を用いたサンプルａ０１では、熱処理温度の上昇とともにＭＲ比が急激に低下し、熱処理温度が４００℃になると、ほとんどＭＲ比を得ることができなかった。また、Ｘとして、熱膨張係数が本発明の範囲外であるＦｅ−Ｐｔ層（熱膨張係数が、Ａｌ2Ｏ3の熱膨張係数よりも３×１０-6／Ｋ大きい）を用いたサンプルａ０８では、２８０℃の熱処理後におけるＭＲ比が他のサンプルよりも小さく、また、熱処理温度の上昇に伴い、サンプルａ０２〜サンプルａ０７に比べてＭＲ比が大きく減少した。 As shown in Table 1, in sample a01 using a soft magnetic material having a thermal expansion coefficient 5 × 10 −6 / K larger than that of Al 2 O 3 as X, the MR ratio increases with the heat treatment temperature. When the temperature rapidly decreased and the heat treatment temperature reached 400 ° C., almost no MR ratio could be obtained. Further, as a sample a08 using an Fe—Pt layer (thermal expansion coefficient is 3 × 10 −6 / K larger than that of Al 2 O 3) having a thermal expansion coefficient outside the scope of the present invention as X. Then, the MR ratio after the heat treatment at 280 ° C. was smaller than that of the other samples, and the MR ratio was greatly reduced as compared with the samples a02 to a07 as the heat treatment temperature increased.

一方、Ｘとして、熱膨張係数が上述の式（１）を満たすインバー合金またはＦｅ基アモルファス合金を用いたサンプルａ０２〜サンプルａ０７では、４００℃の熱処理後においてもＭＲ比の劣化がほとんど見られなかった。インバー合金およびＦｅ基アモルファス合金に代表される低熱膨張磁性膜によって、トンネル絶縁層に加わる応力負荷が抑制され、高い熱処理温度においても、トンネル絶縁層とそれに隣接する磁性層との界面が安定した接合を保っている可能性が考えられる。また、サンプルａ０３では、トンネル絶縁層と低熱膨張磁性膜とが直に接していないにも関わらず、耐熱性に優れる結果が得られた。低熱膨張磁性膜であるＦｅ−Ｐｄ層により、Ｃｏ層とトンネル絶縁層との界面の劣化が抑制されている可能性が考えられる。   On the other hand, as X, in samples a02 to a07 using an Invar alloy or Fe-based amorphous alloy whose thermal expansion coefficient satisfies the above formula (1), the MR ratio hardly deteriorates even after heat treatment at 400 ° C. It was. A low thermal expansion magnetic film typified by Invar alloy and Fe-based amorphous alloy suppresses the stress load applied to the tunnel insulating layer, and the interface between the tunnel insulating layer and the adjacent magnetic layer is stable even at high heat treatment temperatures. There is a possibility that In sample a03, although the tunnel insulating layer and the low thermal expansion magnetic film were not in direct contact with each other, a result with excellent heat resistance was obtained. It is considered that the Fe—Pd layer, which is a low thermal expansion magnetic film, may suppress the deterioration of the interface between the Co layer and the tunnel insulating layer.

（実施例２）
本実施例では、インバー合金からなる低熱膨張磁性膜をトンネル絶縁層の両面に配置したＭＲ素子について、ＭＲ特性の熱処理温度依存性を評価した。 (Example 2)
In this example, the MR characteristics of the MR element in which low thermal expansion magnetic films made of Invar alloy are arranged on both surfaces of the tunnel insulating layer were evaluated.

実施例１と同様の方法を用いて、下記に示す膜構成のＭＲ素子を作製した。   Using the same method as in Example 1, an MR element having the following film structure was produced.

熱酸化膜付Ｓｉ基板／Ｔａ（３）／Ｃｕ（５０）／Ｔａ（３）／Ｎｉ−Ｆｅ−Ｃｒ（４）／Ｐｔ−Ｍｎ（２０）／Ｃｏ−Ｆｅ（３）／Ｒｕ（０．８）／Ｃｏ−Ｆｅ（１）／Ｘ1／Ａｌ2Ｏ3（１）／Ｘ2／Ｎｉ0.8Ｆｅ0.2（５） Si substrate with thermal oxide film / Ta (3) / Cu (50) / Ta (3) / Ni-Fe-Cr (4) / Pt-Mn (20) / Co-Fe (3) / Ru (0.8 ) / Co-Fe (1) / X 1 / Al 2 O 3 (1) / X 2 / Ni 0.8 Fe 0.2 (5)

基板上のＴａ（３）／Ｃｕ（５０）は下部電極であり、下部電極とＰｔ−Ｍｎ（２０）との間のＴａ（３）／Ｎｉ−Ｆｅ−Ｃｒ（４）は下地層である。また、Ｐｔ−Ｍｎ層は反強磁性層であり、Ｃｏ−Ｆｅ（３）／Ｒｕ（０．８）／Ｃｏ−Ｆｅ（１）は、Ｒｕを非磁性膜とする積層フェリ構造である。   Ta (3) / Cu (50) on the substrate is a lower electrode, and Ta (3) / Ni—Fe—Cr (4) between the lower electrode and Pt—Mn (20) is an underlayer. The Pt—Mn layer is an antiferromagnetic layer, and Co—Fe (3) / Ru (0.8) / Co—Fe (1) has a laminated ferrimagnetic structure in which Ru is a nonmagnetic film.

Ｘ1およびＸ2は、以下の表２に示す組成を有する磁性材料である。本実施例では、従来例として１種類（サンプルｂ０１）、また、実施例として５種類のサンプル（サンプルｂ０２〜サンプルｂ０６）を準備した。各サンプルの素子サイズは３μｍ×４μｍとした。なお、Ｐｔ−Ｍｎ層、Ｎｉ−Ｆｅ−Ｃｒ層およびＣｏ−Ｆｅ層の組成は、それぞれＰｔ0.48Ｍｎ0.52、Ｎｉ0.6Ｆｅ0.15Ｃｒ0.25、Ｃｏ0.9Ｆｅ0.1であった。 X 1 and X 2 are magnetic materials having the compositions shown in Table 2 below. In this example, one type (sample b01) was prepared as a conventional example, and five types of samples (sample b02 to sample b06) were prepared as examples. The element size of each sample was 3 μm × 4 μm. Note that the compositions of the Pt—Mn layer, the Ni—Fe—Cr layer, and the Co—Fe layer were Pt 0.48 Mn 0.52 , Ni 0.6 Fe 0.15 Cr 0.25 , and Co 0.9 Fe 0.1 , respectively.

トンネル絶縁層であるＡｌ2Ｏ3は、Ａｌを１．２ｎｍ成膜した後に、純酸素中でプラズマ酸化を６０秒行うことにより作製した。また、各サンプルの作製にあたっては、４．０×１０5Ａ／ｍ（５ｋＯｅ）の磁界中で真空熱処理（３００℃、１０時間）することにより反強磁性層であるＰｔ‐Ｍｎ層へ磁気異方性の付与を行った。 Al 2 O 3 as a tunnel insulating layer was prepared by performing plasma oxidation in pure oxygen for 60 seconds after depositing Al to a thickness of 1.2 nm. Also, in preparing each sample, the Pt—Mn layer, which is an antiferromagnetic layer, was magnetically treated by vacuum heat treatment (300 ° C., 10 hours) in a magnetic field of 4.0 × 10 5 A / m (5 kOe). An impartiality was given.

以下の表２に、Ｘ1およびＸ2の組成、膜厚および熱膨張係数を示す。なお、サンプルｂ０４では、Ｘ2のうち、Ｆｅ0.7Ｐｄ0.3（２）のみが低熱膨張磁性膜に相当し、Ｆｅ（１）は、図４における磁性膜１２に相当する。また、サンプルｂ０４におけるＸ2の熱膨張係数は、低熱膨張磁性膜であるＦｅ0.7Ｐｄ0.3層のみの値である。同様に、サンプルｂ０５では、Ｘ1およびＸ2のうち、Ｆｅ0.75Ｐｔ0.25（３）のみが低熱膨張磁性膜に相当し、Ｃｏ（１）およびＣｏ（１．５）は、図４における磁性膜１２に相当する。サンプルｂ０５におけるＸ1およびＸ2の熱膨張係数は、低熱膨張磁性膜であるＦｅ0.75Ｐｔ0.25層のみの値である。 Table 2 below shows the composition, film thickness, and thermal expansion coefficient of X 1 and X 2 . In sample b04, only Fe 0.7 Pd 0.3 (2) of X 2 corresponds to the low thermal expansion magnetic film, and Fe (1) corresponds to the magnetic film 12 in FIG. Further, the thermal expansion coefficient of X 2 in sample b04 is a value of only the Fe 0.7 Pd 0.3 layer which is a low thermal expansion magnetic film. Similarly, in sample b05, only Fe 0.75 Pt 0.25 (3) of X 1 and X 2 corresponds to the low thermal expansion magnetic film, and Co (1) and Co (1.5) are magnetic films in FIG. This corresponds to 12. The thermal expansion coefficients of X 1 and X 2 in sample b05 are values of only the Fe 0.75 Pt 0.25 layer that is a low thermal expansion magnetic film.

なお、トンネル絶縁層であるＡｌ2Ｏ3の熱膨張係数は８×１０-6／Ｋであった。 In addition, the thermal expansion coefficient of Al 2 O 3 which is a tunnel insulating layer was 8 × 10 −6 / K.

Figure 0003954573
Figure 0003954573

表２に示す各サンプルに対し、ＭＲ特性の熱処理温度依存性を評価した。熱処理は、４．０×１０5Ａ／ｍ（５ｋＯｅ）の磁界中において、以下の表３に示す各熱処理温度にまでサンプルを加熱し、２時間保持した後に室温まで冷却して行った。その後、各サンプルのＭＲ特性としてＭＲ比を求めた。以下の表３に、各サンプルの熱処理温度依存性の結果を示す。 For each sample shown in Table 2, the heat treatment temperature dependence of MR characteristics was evaluated. The heat treatment was performed in a magnetic field of 4.0 × 10 5 A / m (5 kOe) by heating the sample to each heat treatment temperature shown in Table 3 below, holding the sample for 2 hours, and then cooling to room temperature. Thereafter, the MR ratio was obtained as the MR characteristic of each sample. Table 3 below shows the results of the heat treatment temperature dependence of each sample.

Figure 0003954573
Figure 0003954573

表３に示すように、Ｘ1およびＸ2として、熱膨張係数がＡｌ2Ｏ3の熱膨張係数よりも５×１０-6／Ｋ大きい軟磁性材料を用いたサンプルｂ０１では、熱処理温度の上昇とともにＭＲ比が急激に減少し、熱処理温度が４００℃になると、ＭＲ比を全く得ることができないほど素子が劣化した。 As shown in Table 3, in sample b01 using a soft magnetic material whose thermal expansion coefficient is 5 × 10 −6 / K larger than that of Al 2 O 3 as X 1 and X 2 , the heat treatment temperature is increased. At the same time, the MR ratio rapidly decreased, and when the heat treatment temperature reached 400 ° C., the element deteriorated so that the MR ratio could not be obtained at all.

一方、Ｘ1およびＸ2として、熱膨張係数が上述の式（１）を満たす低熱膨張磁性膜を用いたサンプルｂ０２〜サンプルｂ０６では、熱処理温度に関わらず、得られたＭＲ比はサンプルｂ０１に比べて大きく、優れた耐熱性を示した。さらに、サンプルｂ０４およびサンプルｂ０５のように、トンネル絶縁層と低熱膨張磁性膜が直に接しておらず、Ｆｅ、Ｃｏといったトンネル絶縁層よりも熱膨張係数が大きい磁性膜を間に積層した場合においても、多少のＭＲ比の減少はあるものの優れた熱安定性を示した。Ｆｅ−ＰｔおよびＦｅ−Ｐｄなどの低熱膨張磁性膜の存在によって、熱処理温度の上昇に伴うトンネル絶縁層に加わる応力負荷の増大が抑制され、トンネル絶縁層とそれに隣接する磁性膜との界面の乱れが抑制されている可能性が考えられる。 On the other hand, in samples b02 to b06 using low thermal expansion magnetic films whose thermal expansion coefficients satisfy the above formula (1) as X 1 and X 2 , the obtained MR ratio is the same as that of sample b01 regardless of the heat treatment temperature. Compared with large, excellent heat resistance. Further, in the case where the tunnel insulating layer and the low thermal expansion magnetic film are not in direct contact as in sample b04 and sample b05, and a magnetic film having a larger thermal expansion coefficient than the tunnel insulating layer such as Fe and Co is laminated between However, although there was a slight decrease in MR ratio, it showed excellent thermal stability. Due to the presence of low thermal expansion magnetic films such as Fe—Pt and Fe—Pd, an increase in stress load applied to the tunnel insulating layer accompanying an increase in the heat treatment temperature is suppressed, and the interface between the tunnel insulating layer and the adjacent magnetic film is disturbed. It is possible that is suppressed.

また、本実施例では、熱処理後のサンプルｂ０１およびサンプルｂ０３のトンネル絶縁層に対して、透過型電子顕微鏡（ＴＥＭ）による断面観察を行った。２８０℃の熱処理後のサンプルでは、サンプルｂ０１およびサンプルｂ０３の双方とも、トンネル絶縁層とトンネル絶縁層に隣接する磁性層との間に明瞭な界面が観察され、トンネル絶縁層の膜厚も熱処理前と変化なく、かつ、全体に均質であった。これに対して、４００℃の熱処理後のサンプルｂ０１では、トンネル絶縁層とトンネル絶縁層に隣接する磁性層（Ｆｅ層）との間に明瞭な界面が観察されず、トンネル絶縁層の膜厚は不均質に増大していた。この現象は、トンネル絶縁層とそれに隣接する磁性層との間の界面拡散によって生じていると推定される。一方、４００℃の熱処理後のサンプルｂ０３では、２８０℃の熱処理後と同様に、トンネル絶縁層とトンネル絶縁層に隣接する磁性層との界面は明瞭であり、トンネル絶縁層の膜厚の変化もほとんどみられず、全体に均質であった。   Further, in this example, cross-sectional observation with a transmission electron microscope (TEM) was performed on the tunnel insulating layers of Sample b01 and Sample b03 after the heat treatment. In the sample after the heat treatment at 280 ° C., a clear interface is observed between the tunnel insulating layer and the magnetic layer adjacent to the tunnel insulating layer in both the sample b01 and the sample b03, and the film thickness of the tunnel insulating layer is also before the heat treatment. There was no change and it was homogeneous throughout. On the other hand, in the sample b01 after the heat treatment at 400 ° C., a clear interface is not observed between the tunnel insulating layer and the magnetic layer (Fe layer) adjacent to the tunnel insulating layer, and the thickness of the tunnel insulating layer is It increased heterogeneously. This phenomenon is presumed to be caused by interface diffusion between the tunnel insulating layer and the magnetic layer adjacent thereto. On the other hand, in the sample b03 after the heat treatment at 400 ° C., the interface between the tunnel insulating layer and the magnetic layer adjacent to the tunnel insulating layer is clear as in the case of the heat treatment at 280 ° C. It was hardly seen and was homogeneous throughout.

（実施例３）
本実施例では、トンネル絶縁層にＡｌＮを用いたＭＲ素子について、ＭＲ特性の熱処理温度依存性を評価した。 (Example 3)
In this example, the MR characteristic of the MR characteristics using AlN for the tunnel insulating layer was evaluated for the heat treatment temperature dependence of the MR characteristics.

実施例１と同様の方法を用いて、下記に示す膜構成のＭＲ素子を作製した。   Using the same method as in Example 1, an MR element having the following film structure was produced.

熱酸化膜付Ｓｉ基板／Ｔａ（３）／Ｃｕ（５０）／Ｔａ（３）／Ｎｉ−Ｆｅ（４）／Ｘ／ＡｌＮ（１．３）／Ｘ／Ｃｏ（５）／Ｉｒ−Ｍｎ（８）   Si substrate with thermal oxide film / Ta (3) / Cu (50) / Ta (3) / Ni-Fe (4) / X / AlN (1.3) / X / Co (5) / Ir-Mn (8 )

基板上のＴａ（３）／Ｃｕ（５０）は下部電極であり、下部電極とＮｉ−Ｆｅ層との間のＴａ（３）は下地層である。また、Ｉｒ−Ｍｎ層は反強磁性層である。Ｘは、以下の表４に示す組成を有する磁性材料である。本実施例では、従来例として１種類（サンプルｃ０１）、実施例として４種類（サンプルｃ０２〜サンプルｃ０５）のサンプルを準備した。各サンプルの素子サイズは２μｍ×４μｍとした。なお、Ｎｉ−Ｆｅ層、Ｉｒ−Ｍｎ層の組成は、それぞれＮｉ0.8Ｆｅ0.2、Ｉｒ0.2Ｍｎ0.8であった。 Ta (3) / Cu (50) on the substrate is a lower electrode, and Ta (3) between the lower electrode and the Ni—Fe layer is an underlayer. The Ir—Mn layer is an antiferromagnetic layer. X is a magnetic material having the composition shown in Table 4 below. In the present example, one type (sample c01) was prepared as a conventional example, and four types (sample c02 to sample c05) were prepared as examples. The element size of each sample was 2 μm × 4 μm. The compositions of the Ni—Fe layer and the Ir—Mn layer were Ni 0.8 Fe 0.2 and Ir 0.2 Mn 0.8 , respectively.

トンネル絶縁層であるＡｌＮは、Ａｌを１．３ｎｍ成膜後、窒素およびアルゴンの混合ガス中でプラズマ窒化することにより作製した。また、各サンプルの作製にあたっては、４．０×１０5Ａ／ｍ（５ｋＯｅ）の磁界中で真空熱処理（２００℃、８時間）することにより反強磁性層であるＩｒ‐Ｍｎ層へ磁気異方性の付与を行った。 AlN, which is a tunnel insulating layer, was fabricated by plasma nitriding in a mixed gas of nitrogen and argon after Al was formed to a thickness of 1.3 nm. Also, in the preparation of each sample, a magnetic treatment was performed on the Ir-Mn layer, which is an antiferromagnetic layer, by vacuum heat treatment (200 ° C., 8 hours) in a magnetic field of 4.0 × 10 5 A / m (5 kOe). An impartiality was given.

なお、トンネル絶縁層であるＡｌＮの熱膨張係数は、４×１０-6／Ｋであった。 The thermal expansion coefficient of AlN, which is a tunnel insulating layer, was 4 × 10 −6 / K.

上記のようにして準備した各サンプルに対し、ＭＲ特性の熱処理温度依存性を評価した。最初に、真空無磁界中において、２００℃の熱処理温度にまでサンプルを加熱し、３０分間保持した。その後、サンプルを室温まで冷却し、各サンプルのＭＲ特性としてＭＲ比を求めた。この結果を、２００℃の熱処理後のＭＲ比として表４に示す。次に、真空無磁界中において以下の表４に示す各温度にまで各サンプルを加熱し、続いて、４．０×１０5Ａ／ｍ（５ｋＯｅ）の磁界中で１時間保持した後、室温まで冷却して熱処理を完了した。その後、各サンプルのＭＲ特性としてＭＲ比を求めた。 The heat treatment temperature dependence of MR characteristics was evaluated for each sample prepared as described above. First, the sample was heated to a heat treatment temperature of 200 ° C. in a vacuumless magnetic field and held for 30 minutes. Then, the sample was cooled to room temperature, and MR ratio was calculated | required as MR characteristic of each sample. The results are shown in Table 4 as the MR ratio after heat treatment at 200 ° C. Next, each sample was heated to each temperature shown in the following Table 4 in a vacuum non-magnetic field, and subsequently kept in a magnetic field of 4.0 × 10 5 A / m (5 kOe) for 1 hour, and then at room temperature. Until the heat treatment was completed. Thereafter, the MR ratio was obtained as the MR characteristic of each sample.

表４に、各サンプルにおけるＸの組成、膜厚および熱膨張係数とともに、ＭＲ比の熱処理温度依存性の結果を示す。   Table 4 shows the results of the heat treatment temperature dependence of the MR ratio together with the X composition, film thickness, and thermal expansion coefficient of each sample.

Figure 0003954573
Figure 0003954573

表４に示すように、Ｘとして、熱膨張係数が、ＡｌＮの熱膨張係数よりも９×１０-6／Ｋ大きい軟磁性材料を用いたサンプルｃ０１では、熱処理温度の上昇とともにＭＲ比が急激に減少し、熱処理温度４００℃ではＭＲ比を全く得ることができないほど素子が劣化した。 As shown in Table 4, in sample c01 using a soft magnetic material whose thermal expansion coefficient is 9 × 10 −6 / K larger than the thermal expansion coefficient of AlN as X, the MR ratio sharply increases as the heat treatment temperature increases. The device deteriorated so that the MR ratio could not be obtained at all at a heat treatment temperature of 400 ° C.

一方、Ｘとして、熱膨張係数が上述の式（１）を満たす低熱膨張磁性膜を用いたサンプルｃ０２〜サンプルｃ０５では、熱処理温度に関わらず、ほぼ安定したＭＲ比を得ることができ、優れた耐熱性を示した。また、２００℃で熱処理を行った場合に比べて、より高い温度で熱処理を行った場合に、より大きいＭＲ比が得られた。このように、トンネル絶縁層にＡｌＮを用いた場合においても、低熱膨張磁性膜を用いることによって、優れた耐熱性を示すＭＲ素子を得ることができる。   On the other hand, in Sample c02 to Sample c05 using the low thermal expansion magnetic film whose thermal expansion coefficient satisfies the above formula (1) as X, an almost stable MR ratio can be obtained regardless of the heat treatment temperature. It showed heat resistance. Also, a larger MR ratio was obtained when heat treatment was performed at a higher temperature than when heat treatment was performed at 200 ° C. Thus, even when AlN is used for the tunnel insulating layer, an MR element exhibiting excellent heat resistance can be obtained by using the low thermal expansion magnetic film.

（実施例４）
本実施例では、トンネル絶縁層の両面にＦｅ基アモルファス合金からなる低熱膨張磁性膜を配置したＭＲ素子について、ＭＲ特性の熱処理温度依存性を評価した。 Example 4
In this example, the MR characteristics of the MR element in which the low thermal expansion magnetic film made of Fe-based amorphous alloy is arranged on both surfaces of the tunnel insulating layer were evaluated.

実施例１と同様の方法を用いて、下記に示す膜構成のＭＲ素子を作製した。   Using the same method as in Example 1, an MR element having the following film structure was produced.

熱酸化膜付Ｓｉ基板／Ｔａ（３）／Ｃｕ（５０）／Ｔａ（３）／Ｎｉ−Ｆｅ（３）／Ｐｔ−Ｍｎ（２０）／Ｃｏ−Ｆｅ（４）／Ｘ／Ａｌ2Ｏ3（１．２）／Ｘ／Ｎｉ0.8Ｆｅ0.2（８） Si substrate with thermal oxide film / Ta (3) / Cu (50) / Ta (3) / Ni—Fe (3) / Pt—Mn (20) / Co—Fe (4) / X / Al 2 O 3 ( 1.2) / X / Ni 0.8 Fe 0.2 (8)

基板上のＴａ（３）／Ｃｕ（５０）は下部電極であり、下部電極とＮｉ−Ｆｅ層との間のＴａ（３）は下地層である。また、Ｐｔ−Ｍｎ層は反強磁性層であり、その組成はＰｔ0.48Ｍｎ0.52であった。Ｘは、以下の表５に示す組成を有する磁性材料である。本実施例では、従来例として１種類（サンプルｄ０１）、実施例として３種類（サンプルｄ０２〜サンプルｄ０４）のサンプルを準備した。各サンプルの素子サイズは２μｍ×２．５μｍとした。なお、Ｎｉ−Ｆｅ層、Ｃｏ−Ｆｅ層の組成は、それぞれＮｉ0.8Ｆｅ0.2、Ｃｏ0.75Ｆｅ0.25であった。 Ta (3) / Cu (50) on the substrate is a lower electrode, and Ta (3) between the lower electrode and the Ni—Fe layer is an underlayer. The Pt—Mn layer was an antiferromagnetic layer, and its composition was Pt 0.48 Mn 0.52 . X is a magnetic material having the composition shown in Table 5 below. In this example, one type (sample d01) was prepared as a conventional example, and three types (sample d02 to sample d04) were prepared as examples. The element size of each sample was 2 μm × 2.5 μm. The compositions of the Ni—Fe layer and the Co—Fe layer were Ni 0.8 Fe 0.2 and Co 0.75 Fe 0.25 , respectively.

トンネル絶縁層であるＡｌ2Ｏ3は、Ａｌを０．３〜０．７ｎｍ成膜後、２６．３ｋＰａ（２００Ｔｏｒｒ）の酸素含有雰囲気中において１分間の酸化を繰り返して作製した。また、各サンプルの作製にあたっては、４．０×１０5Ａ／ｍ（５ｋＯｅ）の磁界中で真空熱処理（２６０℃、８時間）することにより反強磁性層であるＰｔ‐Ｍｎ層へ磁気異方性の付与を行った。 Al 2 O 3 which is a tunnel insulating layer was formed by repeating oxidation for 1 minute in an oxygen-containing atmosphere of 26.3 kPa (200 Torr) after depositing Al in a thickness of 0.3 to 0.7 nm. Also, in the preparation of each sample, the Pt—Mn layer, which is an antiferromagnetic layer, was magnetically treated by vacuum heat treatment (260 ° C., 8 hours) in a magnetic field of 4.0 × 10 5 A / m (5 kOe). An impartiality was given.

なお、トンネル絶縁層であるＡｌ2Ｏ3の熱膨張係数は、８×１０-6／Ｋであった。 In addition, the thermal expansion coefficient of Al 2 O 3 which is a tunnel insulating layer was 8 × 10 −6 / K.

上記のようにして準備した各サンプルに対し、ＭＲ特性の熱処理温度依存性を評価した。熱処理は、真空無磁界中において以下の表５に示す各温度にまで各サンプルを加熱し、１時間保持した後に室温まで冷却して行った。その後、各サンプルのＭＲ特性としてＭＲ比を求めた。   The heat treatment temperature dependence of MR characteristics was evaluated for each sample prepared as described above. The heat treatment was performed by heating each sample to each temperature shown in Table 5 below in a vacuum magnetic field, holding the sample for 1 hour, and then cooling to room temperature. Thereafter, the MR ratio was obtained as the MR characteristic of each sample.

表５に、各サンプルにおけるＸの組成、膜厚および熱膨張係数とともに、ＭＲ比の熱処理温度依存性の結果を示す。   Table 5 shows the results of the heat treatment temperature dependence of the MR ratio together with the X composition, film thickness, and thermal expansion coefficient of each sample.

Figure 0003954573
Figure 0003954573

表５に示すように、Ｘとして、熱膨張係数が、Ａｌ2Ｏ3の熱膨張係数よりも４×１０-6／Ｋ大きい軟磁性材料を用いたサンプルｄ０１では、熱処理温度の上昇とともにＭＲ比が急激に低下し、熱処理温度が４００℃になると、ほとんどＭＲ比を得ることができなかった。これに対し、Ｘとして、熱膨張係数が上述の式（１）を満たすＦｅ基アモルファス合金を用いたサンプルｄ０２〜サンプルｄ０４は、耐熱性に優れるＭＲ素子であることがわかった。 As shown in Table 5, as sample X01 using a soft magnetic material whose thermal expansion coefficient is 4 × 10 −6 / K larger than that of Al 2 O 3 as X, the MR ratio increases as the heat treatment temperature increases. When the temperature dropped rapidly and the heat treatment temperature reached 400 ° C., the MR ratio could hardly be obtained. On the other hand, it was found that Sample d02 to Sample d04 using an Fe-based amorphous alloy satisfying the above formula (1) as X are MR elements having excellent heat resistance.

なお、上述の実施例１〜４において、Ｘとして（あるいは、Ｘ1、Ｘ2として）、式Ｆｅx−Ｎｉy−Ｃｏz（ｘ＋ｙ＋ｚ＝１、０．５≦ｘ≦０．７、０．３≦ｙ≦０．４５、０≦ｚ≦０．２）で示される組成を有する合金や、式Ｆｅ1-a−Ｐｔa（０．１５≦ａ≦０．４５）で示される組成を有する合金、式Ｆｅ1-b−Ｐｄb（０．２≦ｂ≦０．４５）で示される組成を有する合金などを用いた場合にも、耐熱性に優れるＭＲ素子を得ることができた。なお、これらの合金の熱膨張係数は、上述の式（１）を満たすものであった。 In Examples 1 to 4 described above, as X (or, as X 1, X 2), wherein Fe x -Ni y -Co z (x + y + z = 1,0.5 ≦ x ≦ 0.7,0. or an alloy having a composition represented by 3 ≦ y ≦ 0.45,0 ≦ z ≦ 0.2), having a composition represented by the formula Fe 1-a -Pt a (0.15 ≦ a ≦ 0.45) Even when an alloy, an alloy having a composition represented by the formula Fe 1-b -Pd b (0.2 ≦ b ≦ 0.45), or the like was used, an MR element having excellent heat resistance could be obtained. In addition, the thermal expansion coefficient of these alloys satisfy | filled above-mentioned Formula (1).

同様に、Ｘとして（あるいは、Ｘ1、Ｘ2として）、式Ｆｅ1-c−Ｍc（０．０５≦ｃ≦０．３、Ｍは、Ｂ、Ｐ、Ｓｉ、ＺｒおよびＨｆから選ばれる少なくとも一種の元素である）で示される組成を有する磁性材料を用いた場合にも、耐熱性に優れるＭＲ素子を得ることができた。なお、上記磁性材料の熱膨張係数は、上述の式（１）を満たすものであった。 Similarly, as X (or as X 1 and X 2 ), the formula Fe 1-c -M c (0.05 ≦ c ≦ 0.3, M is selected from B, P, Si, Zr and Hf) Even when a magnetic material having a composition represented by (at least one kind of element) was used, an MR element having excellent heat resistance could be obtained. Note that the thermal expansion coefficient of the magnetic material satisfied the above formula (1).

（実施例５）
実施例２で作製したＭＲ素子（サンプルｂ０１、サンプルｂ０２、サンプルｂ０３）を用いて図１０に示すようなシールドを備えた磁気ヘッドを作製し、その特性を評価した。 (Example 5)
Using the MR element (sample b01, sample b02, sample b03) produced in Example 2, a magnetic head provided with a shield as shown in FIG. 10 was produced, and its characteristics were evaluated.

磁気ヘッドを作製するにあたっては、磁気ヘッドの基板にＡｌ2Ｏ3−ＴｉＣ基板を、上部記録コア、上部シールドおよび下部シールドにＮｉ0.8Ｆｅ0.2合金を用いた。また、ＭＲ素子を狭持する電極には、Ｃｕ、ＰｔおよびＴａの積層膜を用いた。 In manufacturing the magnetic head, an Al 2 O 3 —TiC substrate was used for the magnetic head substrate, and an Ni 0.8 Fe 0.2 alloy was used for the upper recording core, upper shield, and lower shield. In addition, a laminated film of Cu, Pt and Ta was used as an electrode for sandwiching the MR element.

ＭＲ素子には、自由磁性層に相当する磁性層の磁化容易方向が検知すべき信号磁界の方向と垂直となるように、また、固定磁性層に相当する磁性層の磁化方向が検知すべき信号磁界の方向と平行になるように、異方性を付与した。このような異方性は、ＭＲ素子を作製した後、最初に固定磁性層の磁化方向を磁界中熱処理（２８０℃、４．０×１０5Ａ／ｍ（５ｋＯｅ））によって規定し、次に自由磁性層の磁化容易方向を磁界中熱処理（２００℃、８．０×１０5Ａ／ｍ（１０ｋＯｅ））によって規定することで付与した。なお、ＭＲ素子のサイズは、０．５μｍ×０．５μｍとした。 In the MR element, the direction of easy magnetization of the magnetic layer corresponding to the free magnetic layer is perpendicular to the direction of the signal magnetic field to be detected, and the magnetization direction of the magnetic layer corresponding to the fixed magnetic layer is to be detected. Anisotropy was imparted so as to be parallel to the direction of the magnetic field. Such anisotropy is defined by first determining the magnetization direction of the pinned magnetic layer by a heat treatment in a magnetic field (280 ° C., 4.0 × 10 5 A / m (5 kOe)) after the MR element is manufactured. The direction of easy magnetization of the free magnetic layer was imparted by defining it by heat treatment in a magnetic field (200 ° C., 8.0 × 10 5 A / m (10 kOe)). The size of the MR element was 0.5 μm × 0.5 μm.

上記のように作製した磁気ヘッドを１５０℃の恒温槽に入れ、５００ｍＶの電圧をＭＲ素子に印加した状態で１０日間保持する試験を実施し、試験の前後におけるＭＲ出力を比較した。ＭＲ出力の測定は以下に示す方法を用いた。   The magnetic head produced as described above was placed in a thermostat at 150 ° C., and a test was carried out for 10 days while a voltage of 500 mV was applied to the MR element, and the MR output before and after the test was compared. The MR output was measured using the following method.

ヘルムホイルコイル中に磁気ヘッドを設置し、ＭＲ素子に電流を印加しながら、その際に得られる磁気抵抗を直流四端子法により測定した。磁気抵抗の測定にあたっては、測定磁界を±４．０×１０4Ａ／ｍの範囲内で変化させた。このようにして得られた磁気抵抗の最大値と最小値の差を磁気ヘッドのＭＲ出力とした。なお、ヘルムホルツコイルにより発生させる測定磁界の方向は、ＭＲ素子の固定磁性層の磁化容易方向とした。 A magnetic head was installed in the Helm foil coil, and while applying a current to the MR element, the magnetic resistance obtained at that time was measured by a DC four-terminal method. In measuring the magnetic resistance, the measurement magnetic field was changed within a range of ± 4.0 × 10 4 A / m. The difference between the maximum value and the minimum value of the magnetic resistance obtained in this way was used as the MR output of the magnetic head. Note that the direction of the measurement magnetic field generated by the Helmholtz coil was set to the easy magnetization direction of the pinned magnetic layer of the MR element.

評価の結果、ＭＲ素子としてサンプルｂ０１を用いた磁気ヘッドでは、試験前後において約４５％の非常に大きな出力低下が発生した。これに対し、ＭＲ素子としてサンプルｂ０２、サンプルｂ０３を用いた磁気ヘッドでは、試験前後の出力の低下は約２％以内であり、試験後も非常に安定した出力特性を示した。   As a result of the evaluation, in the magnetic head using the sample b01 as the MR element, a very large output decrease of about 45% occurred before and after the test. On the other hand, in the magnetic head using the sample b02 and the sample b03 as the MR element, the decrease in output before and after the test was within about 2%, and very stable output characteristics were exhibited after the test.

（実施例６）
実施例１で作製したＭＲ素子（サンプルａ０１、サンプルａ０３）ならびに実施例２で作製したＭＲ素子（サンプルｂ０３、サンプルｂ０５）を用いて、図１１および図１２に示すようなヨークを備えた磁気ヘッドを作製した。 (Example 6)
A magnetic head provided with a yoke as shown in FIG. 11 and FIG. 12 using the MR element (sample a01, sample a03) produced in Example 1 and the MR element (sample b03, sample b05) produced in Example 2. Was made.

磁気ヘッドの作製にあたっては、基板にＭｎ−Ｚｎフェライト基板を用い、この基板が下部ヨークを兼ねる構造とした。また、基板上にＡｌ2Ｏ3を用いて絶縁層を形成し、その上にＭＲ素子を作製した。上部ヨークにはＣｏＺｒＴａ軟磁性材料を用い、絶縁層部にはＡｌ2Ｏ3を用いた。また、ハードバイアス部にはＣｏＰｔ合金を用い、リード部にはＣｕ、ＴａおよびＰｔの積層膜を用いた。ＭＲ素子の形状は、図１１に示すＭＲ高さ５３９、図１２に示すＭＲ幅５４０ともに８μｍとした。 In manufacturing the magnetic head, a Mn—Zn ferrite substrate was used as the substrate, and this substrate also served as the lower yoke. In addition, an insulating layer was formed on the substrate using Al 2 O 3 , and an MR element was fabricated thereon. A CoZrTa soft magnetic material was used for the upper yoke, and Al 2 O 3 was used for the insulating layer. Further, a CoPt alloy was used for the hard bias portion, and a laminated film of Cu, Ta and Pt was used for the lead portion. The shape of the MR element was 8 μm for both the MR height 539 shown in FIG. 11 and the MR width 540 shown in FIG.

ＭＲ素子には、実施例５と同様に、自由磁性層に相当する磁性層の磁化容易方向が検知すべき信号磁界の方向と垂直になるように、また、固定磁性層にあたる磁性層の磁化方向が検知すべき信号磁界の方向と平行になるように異方性を付与した。なお、磁気ヘッドの再生ギャップ長は０．１μｍとした。   In the MR element, as in the fifth embodiment, the direction of easy magnetization of the magnetic layer corresponding to the free magnetic layer is perpendicular to the direction of the signal magnetic field to be detected, and the magnetization direction of the magnetic layer corresponding to the fixed magnetic layer Is given anisotropy so as to be parallel to the direction of the signal magnetic field to be detected. The reproducing gap length of the magnetic head was set to 0.1 μm.

上記のように作製した磁気ヘッドを、１６０℃の恒温槽に入れ、２００ｍＶの電圧をＭＲ素子に印加した状態で５０日間保持するという試験を実施し、試験前後のＭＲ出力を比較した。ＭＲ出力の測定は実施例５と同様の方法を用いた。   The magnetic head manufactured as described above was placed in a constant temperature bath at 160 ° C., and a test was carried out for 50 days with a voltage of 200 mV applied to the MR element, and the MR output before and after the test was compared. The MR output was measured using the same method as in Example 5.

評価の結果、ＭＲ素子としてサンプルａ０１を用いた磁気ヘッドでは、試験前後において約５０％の非常に大きな出力低下が発生した。これに対して、ＭＲ素子としてサンプルａ０３、サンプルｂ０３、サンプルｂ０５を用いた磁気ヘッドでは、試験前後の出力の低下が約１％以内であり、試験後も非常に安定した出力特性を示した。   As a result of the evaluation, in the magnetic head using the sample a01 as the MR element, a very large output reduction of about 50% occurred before and after the test. In contrast, in the magnetic head using the sample a03, the sample b03, and the sample b05 as the MR elements, the decrease in the output before and after the test was within about 1%, and very stable output characteristics were exhibited after the test.

（実施例７）
実施例１で作製したＭＲ素子（サンプルａ０１、サンプルａ０２）を用いて、図１７に示すような磁気メモリ（ＭＲＡＭ）を作製した。 (Example 7)
Using the MR element (sample a01, sample a02) manufactured in Example 1, a magnetic memory (MRAM) as shown in FIG. 17 was manufactured.

ＭＲＡＭの作製は以下のように行った。まず、３００ｎｍの熱酸化膜を有するＳｉ基板上に、Ｃｕからなるワード線を形成し、その表面にＡｌ2Ｏ3絶縁膜を成膜して形成した後、Ｃｕからなる下部電極を形成した。ここでＣＭＰにより下部電極表面の平滑化を行った後、サンプルａ０１またはサンプルａ０２に示す膜構成のＭＲ素子を積層させた。 The MRAM was manufactured as follows. First, a word line made of Cu was formed on a Si substrate having a 300 nm thermal oxide film, an Al 2 O 3 insulating film was formed on the surface, and then a lower electrode made of Cu was formed. Here, after smoothing the surface of the lower electrode by CMP, MR elements having the film configuration shown in sample a01 or sample a02 were laminated.

次に、反強磁性層であるＰｔ−Ｍｎ層と固定磁性層との間に交換結合磁界が生じるように、２８０℃、４．０×１０5Ａ／ｍ（５ｋＯｅ）の磁界中熱処理を５時間行った。その後、実施例１と同様に、メサ型に微細加工することによって、ＭＲ素子を形成した。最後に、上部電極としてビット線を形成し、図１７に示すようなスイッチ素子を持たない単一磁気メモリを作製した。 Next, a heat treatment in a magnetic field of 280 ° C. and 4.0 × 10 5 A / m (5 kOe) is performed so that an exchange coupling magnetic field is generated between the Pt—Mn layer, which is an antiferromagnetic layer, and the pinned magnetic layer. Went for hours. Thereafter, in the same manner as in Example 1, an MR element was formed by microfabrication into a mesa shape. Finally, a bit line was formed as the upper electrode, and a single magnetic memory having no switching element as shown in FIG. 17 was produced.

作製した磁気メモリに対して、ワード線およびビット線に電流を流して磁界を発生させ、ＭＲ素子の自由磁性層（本実施例では両サンプルともに、Ｎｉ−Ｆｅ（５））の磁化方向を反転させて情報「０」を記録した。次に、ワード線とビット線に対して先程とは逆方向の電流を流して磁界を発生させ、自由磁性層の磁化方向を反転させて情報「１」を記録した。その後、それぞれの状態のＭＲ素子に対してバイアス電圧を印加することによってセンス電流を流し、情報「０」と情報「１」の状態における素子電圧の差を測定したところ、両サンプルとも同程度の出力差が得られた。よって、双方のサンプルともに自由磁性層を情報記録層とする磁気メモリとなっていることがわかった。   A magnetic field is generated by passing a current through the word line and the bit line for the fabricated magnetic memory, and the magnetization direction of the free magnetic layer of the MR element (in this example, both samples are Ni-Fe (5)) is reversed. Information “0” was recorded. Next, a current in the opposite direction to the word line and the bit line was passed to generate a magnetic field, and the magnetization direction of the free magnetic layer was reversed to record information “1”. Thereafter, a sense current was passed by applying a bias voltage to the MR element in each state, and the difference in element voltage between the information “0” and information “1” states was measured. An output difference was obtained. Therefore, it was found that both samples were magnetic memories having a free magnetic layer as an information recording layer.

次に、上記のＭＲ素子をＣＭＯＳ基板上に配置し、図１４に示すような集積磁気メモリを作製した。素子配列は、１６×１６素子のメモリを１ブロックとして、合計８ブロックとした。ＭＲ素子の配置は、次のように行った。まずＣＭＯＳ基板上に、スイッチ素子としてＦＥＴをマトリックス状に配置し、ＣＭＰで表面を平坦化した後、サンプルａ０２またはサンプルａ０１のＭＲ素子をＦＥＴに対応してマトリックス状に配置した。ＭＲ素子の配置後、水素シンター処理を４００℃にて行った。なお、各ブロック中１素子は、配線抵抗や素子最低抵抗、ＦＥＴ抵抗などをキャンセルするためのダミー素子とした。また、ワード線、ビット線などは全てＣｕを用い、それぞれの素子サイズは０．１μｍ×０．１５μｍとした。   Next, the MR element described above was placed on a CMOS substrate to produce an integrated magnetic memory as shown in FIG. The element arrangement was 8 blocks in total, with a 16 × 16 element memory as one block. The arrangement of the MR element was performed as follows. First, FETs as switching elements were arranged in a matrix on a CMOS substrate, the surface was planarized by CMP, and the MR elements of sample a02 or sample a01 were arranged in a matrix corresponding to the FETs. After the placement of the MR element, hydrogen sintering was performed at 400 ° C. One element in each block was a dummy element for canceling wiring resistance, element minimum resistance, FET resistance, and the like. Further, all of the word lines, bit lines, etc. were made of Cu, and the respective element sizes were set to 0.1 μm × 0.15 μm.

このように作製した磁気メモリに対し、ワード線およびビット線によって生じた合成磁界により、各ブロックそれぞれ８素子の自由磁性層の磁化反転を同時に行い、信号を記録させた。次に、ＦＥＴのゲートを、それぞれのブロックに付き１素子づつＯＮし、素子にセンス電流を流した。このとき、各ブロック内におけるビット線、素子およびＦＥＴに発生する電圧と、ダミー電圧とをコンパレータにより比較し、それぞれの素子の出力を読みとった。   With respect to the magnetic memory manufactured in this manner, the magnetization reversal of the free magnetic layers of 8 elements in each block was simultaneously performed by the combined magnetic field generated by the word lines and the bit lines, and signals were recorded. Next, the gate of the FET was turned on one element at a time for each block, and a sense current was passed through the element. At this time, the voltage generated in the bit line, element and FET in each block was compared with the dummy voltage by a comparator, and the output of each element was read.

測定の結果、ＭＲ素子としてサンプルａ０１を用いたＭＲＡＭでは、全く素子出力が得られなかった。一方、ＭＲ素子としてサンプルａ０２を用いたＭＲＡＭでは、上述の単一磁気メモリの場合と同様に、良好な素子出力が得られた。この結果から、サンプルａ０１が、おそらく実施例１に上述した原因から、４００℃の熱処理に耐えられなかったのに対し、サンプルａ０２は４００℃の熱処理に対しても十分な耐熱性を有していたといえる。   As a result of the measurement, no element output was obtained with the MRAM using the sample a01 as the MR element. On the other hand, in the MRAM using the sample a02 as the MR element, a good element output was obtained as in the case of the single magnetic memory described above. From this result, sample a01 was not able to withstand the heat treatment at 400 ° C., possibly due to the above-described cause in Example 1, whereas sample a02 had sufficient heat resistance even at the heat treatment at 400 ° C. It can be said that.

本発明は、その意図および本質的な特徴から逸脱しない限り、他の実施の形態に適用しうる。この明細書に開示されている実施の形態は、あらゆる点で説明的なものであってこれに限定されない。本発明の範囲は、上記説明ではなく添付したクレームによって示されており、クレームと均等な意味および範囲にあるすべての変更はそれに含まれる。   The present invention can be applied to other embodiments without departing from the spirit and essential characteristics thereof. The embodiment disclosed in this specification is illustrative in all respects and is not limited thereto. The scope of the present invention is shown not by the above description but by the appended claims, and all modifications that fall within the meaning and scope equivalent to the claims are embraced therein.

以上説明したように、本発明によれば、耐熱性に優れる磁気抵抗効果素子を得ることができる。また、本発明の磁気抵抗効果素子を用いることで、耐熱性に優れる磁気ヘッドおよび磁気メモリ素子、ならびに磁気記録装置を得ることができる。   As described above, according to the present invention, a magnetoresistive effect element having excellent heat resistance can be obtained. In addition, by using the magnetoresistive effect element of the present invention, a magnetic head, a magnetic memory element, and a magnetic recording apparatus having excellent heat resistance can be obtained.

本発明の磁気抵抗効果素子の一例を示す断面図である。It is sectional drawing which shows an example of the magnetoresistive effect element of this invention. 本発明の磁気抵抗効果素子の別の一例を示す断面図である。It is sectional drawing which shows another example of the magnetoresistive effect element of this invention. 本発明の磁気抵抗効果素子のまた別の一例を示す断面図である。It is sectional drawing which shows another example of the magnetoresistive effect element of this invention. 本発明の磁気抵抗効果素子のさらに別の一例を示す断面図である。It is sectional drawing which shows another example of the magnetoresistive effect element of this invention. 本発明の磁気抵抗効果素子のまたさらに別の一例を示す断面図である。It is sectional drawing which shows another example of the magnetoresistive effect element of this invention. 本発明の磁気抵抗効果素子の上記とは別の一例を示す断面図である。It is sectional drawing which shows an example different from the above of the magnetoresistive effect element of this invention. 本発明の磁気抵抗効果素子の上記とはまた別の一例を示す断面図である。It is sectional drawing which shows another example from the above of the magnetoresistive effect element of this invention. 本発明の磁気抵抗効果素子の上記とはさらに別の一例を示す断面図である。It is sectional drawing which shows another example from the above of the magnetoresistive effect element of this invention. 電極をさらに配置した本発明の磁気抵抗効果素子の一例を示す断面図である。It is sectional drawing which shows an example of the magnetoresistive effect element of this invention which has further arrange | positioned the electrode. 本発明の磁気ヘッドの一例と記録再生方法の一例とを示す模式図である。It is a schematic diagram which shows an example of the magnetic head of this invention, and an example of the recording / reproducing method. 本発明の磁気ヘッドの一例を示す断面図である。It is sectional drawing which shows an example of the magnetic head of this invention. 図１１に示す磁気ヘッドの構造の一例を示す断面図である。It is sectional drawing which shows an example of the structure of the magnetic head shown in FIG. 本発明の磁気記録装置の一例を示す模式図である。It is a schematic diagram which shows an example of the magnetic recording device of this invention. 本発明の磁気メモリの一例を示す模式図である。It is a schematic diagram which shows an example of the magnetic memory of this invention. 図１５Ａおよび図１５Ｂは、本発明の磁気メモリにおける動作の基本例を示す模式図である。15A and 15B are schematic views showing a basic example of the operation in the magnetic memory of the present invention. 図１６Ａおよび図１６Ｂは、本発明の磁気メモリにおける動作の基本例を示す模式図である。16A and 16B are schematic views showing a basic example of the operation in the magnetic memory of the present invention. 図１７Ａおよび図１７Ｂは、本発明の磁気メモリにおける動作の基本例を示す模式図である。17A and 17B are schematic views showing a basic example of the operation in the magnetic memory of the present invention.

Claims (17)

トンネル絶縁層と、前記トンネル絶縁層を介して積層された一対の磁性層とを含む多層膜構造を含み、
双方の前記磁性層が有する磁化方向の相対角度により抵抗値が異なり、
前記磁性層の少なくとも一方が、前記トンネル絶縁層の熱膨張係数に２×１０-6／Ｋを加えた値以下の熱膨張係数を有する磁性膜を含む磁気抵抗効果素子。A multilayer structure including a tunnel insulating layer and a pair of magnetic layers stacked via the tunnel insulating layer;
The resistance value differs depending on the relative angle of the magnetization direction of both the magnetic layers,
A magnetoresistive effect element, wherein at least one of the magnetic layers includes a magnetic film having a thermal expansion coefficient equal to or less than a value obtained by adding 2 × 10 −6 / K to the thermal expansion coefficient of the tunnel insulating layer. 前記磁性膜の熱膨張係数が、前記トンネル絶縁層の熱膨張係数以下である請求項１に記載の磁気抵抗効果素子。The magnetoresistive element according to claim 1, wherein a thermal expansion coefficient of the magnetic film is equal to or less than a thermal expansion coefficient of the tunnel insulating layer. 前記磁性膜が、前記トンネル絶縁層に接している請求項１に記載の磁気抵抗効果素子。The magnetoresistive element according to claim 1, wherein the magnetic film is in contact with the tunnel insulating layer. 前記トンネル絶縁層が、Ａｌの酸化物、窒化物および酸窒化物から選ばれる少なくとも１種の化合物を含む請求項１に記載の磁気抵抗効果素子。2. The magnetoresistive element according to claim 1, wherein the tunnel insulating layer includes at least one compound selected from an oxide, nitride, and oxynitride of Al. 前記磁性膜が、インバー合金を含む請求項１に記載の磁気抵抗効果素子。The magnetoresistive element according to claim 1, wherein the magnetic film includes an Invar alloy. 前記磁性膜が、Ｆｅを主成分とするアモルファス合金を含む請求項１に記載の磁気抵抗効果素子。The magnetoresistive element according to claim 1, wherein the magnetic film includes an amorphous alloy containing Fe as a main component. 前記インバー合金が、式Ｆｅx−Ｎｉy−Ｃｏzで示される組成を有する請求項５に記載の磁気抵抗効果素子。
ただし、式Ｆｅx−Ｎｉy−Ｃｏzにおいて、ｘ、ｙ、ｚは、それぞれ以下の式を満たす数値である。
ｘ＋ｙ＋ｚ＝１
０．５≦ｘ≦０．７
０．３≦ｙ≦０．４５
０≦ｚ≦０．２The Invar alloy, the magnetoresistance effect element according to claim 5 having a composition represented by the formula Fe x -Ni y -Co z.
However, in the formula Fe x -Ni y -Co z, x , y, z are numerical values satisfying the following equations, respectively.
x + y + z = 1
0.5 ≦ x ≦ 0.7
0.3 ≦ y ≦ 0.45
0 ≦ z ≦ 0.2 前記インバー合金が、式Ｆｅ1-a−Ｐｔaで示される組成を有する請求項５に記載の磁気抵抗効果素子。
ただし、式Ｆｅ1-a−Ｐｔaにおいて、ａは、以下の式を満たす数値である。
０．１５≦ａ≦０．４５The magnetoresistive element according to claim 5, wherein the Invar alloy has a composition represented by a formula Fe 1-a -Pta.
However, in the formula Fe 1-a -Pt a, a is a numerical value satisfying the following equation.
0.15 ≦ a ≦ 0.45 前記インバー合金が、式Ｆｅ1-b−Ｐｄbで示される組成を有する請求項５に記載の磁気抵抗効果素子。
ただし、式Ｆｅ1-b−Ｐｄbにおいて、ｂは、以下の式を満たす数値である。
０．２≦ｂ≦０．４５The Invar alloy, the magnetoresistance effect element according to claim 5 having a composition represented by the formula Fe 1-b -Pd b.
However, in the formula Fe 1-b -Pd b, b is a numerical value satisfying the following equation.
0.2 ≦ b ≦ 0.45 前記アモルファス合金が、式Ｆｅ1-c−Ｍcで示される組成を有する請求項６に記載の磁気抵抗効果素子。
ただし、式Ｆｅ1-c−Ｍcにおいて、Ｍは、Ｂ、Ｐ、Ｓｉ、ＺｒおよびＨｆから選ばれる少なくとも１種の元素であり、
ｃは、以下の式を満たす数値である。
０．０５≦ｃ≦０．３The magnetoresistive element according to claim 6, wherein the amorphous alloy has a composition represented by a formula Fe 1-c -M c .
However, in the formula Fe 1-c -M c , M is at least one element selected from B, P, Si, Zr and Hf,
c is a numerical value satisfying the following expression.
0.05 ≦ c ≦ 0.3 反強磁性層をさらに含む請求項１に記載の磁気抵抗効果素子。The magnetoresistive effect element according to claim 1, further comprising an antiferromagnetic layer. 前記反強磁性層が、Ｍｎを含む請求項１１に記載の磁気抵抗効果素子。The magnetoresistive element according to claim 11, wherein the antiferromagnetic layer contains Mn. 請求項１に記載の磁気抵抗効果素子と、前記磁気抵抗効果素子により検知すべき磁界以外の磁界の、前記磁気抵抗効果素子への導入を制限するシールドとを含む磁気ヘッド。A magnetic head comprising: the magnetoresistive effect element according to claim 1; and a shield that limits introduction of a magnetic field other than the magnetic field to be detected by the magnetoresistive effect element into the magnetoresistive effect element. 請求項１に記載の磁気抵抗効果素子と、前記磁気抵抗効果素子により検知すべき磁界を前記磁気抵抗効果素子へ導入するヨ−クとを含む磁気ヘッド。A magnetic head comprising the magnetoresistive effect element according to claim 1 and a yoke for introducing a magnetic field to be detected by the magnetoresistive effect element into the magnetoresistive effect element. 請求項１に記載の磁気抵抗効果素子と、前記磁気抵抗効果素子に情報を記録するための情報記録用導体線と、前記情報を読み出すための情報読出用導体線とを含む磁気メモリ。A magnetic memory comprising: the magnetoresistive effect element according to claim 1; an information recording conductor line for recording information on the magnetoresistive element; and an information read conductor line for reading the information. 請求項１３に記載の磁気ヘッドと、前記磁気ヘッドにより磁気情報を読み出すことができる磁気記録媒体とを含む磁気記録装置。A magnetic recording apparatus comprising: the magnetic head according to claim 13; and a magnetic recording medium from which magnetic information can be read by the magnetic head. 請求項１４に記載の磁気ヘッドと、前記磁気ヘッドにより磁気情報を読み出すことができる磁気記録媒体とを含む磁気記録装置。15. A magnetic recording apparatus comprising: the magnetic head according to claim 14; and a magnetic recording medium from which magnetic information can be read by the magnetic head.
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